S3IITHSONIAN MISCELLANEOUS COLLECTIONS.
145
MONOGRAPH
OF
AMERICAN  CORBICULADIE.
(RECENT AND FOSSIL.)
PREPARED FOR THE SMITHSONIAN INSTITUTION.
BY
TEMPLE PRIME.
WASHINGTON:
SMITHSONIAN INSTITUTION.
DECEMBER, 1865.








PREF ACE.
IN the present MONOGRAPH OF AMERICAN CORBICULAD., prepared at the request of the Smithsonian Institution, it is proposed
to show the present state of our knowledge of the species, both
recent and fossil, which inhabit North and South America.  It
contains descriptions of all the genera of the family, whether
represented on this continent or not, descriptions of the species
found in North and South America, notices of their geographical
range, references to the collections in which authentic types of
many of the species are known to exist, and comparisons of the
different species with others of the same genus, indigenous and
foreign.
I have been able to identify to my entire satisfaction very nearly
all the species described as from America, and the instances in
which I have not been successful, are duly noted in the text
accompanying the description of the species.
I am aware of the fact that some of the genera adopted in these
pages, based chiefly upon characters drawn from the shell alone,
ought not to be retai~ed with their present limits; nevertheless
our knowledge of the soft parts of the species of this family is
still so very imperfect that no other course is open to me but to 
preserve for the present the genera as I find them, however defective they may actually be.
It will soon be necessary, in order to keep pace with other
departments of natural history, to introduce some modifications
in the limits of the genera of the Corbiculadw, but no really satisfactory or permanent result will be attained until a careful examination of the soft parts shall have been made.
I am at present engaged upon a new arrangement of the genera
of the Corbiculade, based upon characters drawn from the soft
parts and from the shell, and in order to call attention to this
( iii )




IV                         PREFACE.
subject, and to have it examined into by those conversant with
it, I give a general outline of some of the changes which I
think, in the present state of our knowledge of this family, might
be made with advantage.
In the first place I propose to separate the American recent
species of the genus Corbicula from the species of this genus inhabiting other regions, for the reason that in the American species
the palleal impression is terminated in a sinus, whereas in the
foreign species it is simple.  This is a character derived from the
soft parts, though the knowledge of it is conveyed to us by an
examination of the shell. The same distinctions exist between
the American recent species of the genus Cyrena and the foreign
species of that genus; it may, therefore, likewise be advisable to
constitute a separate genus for the American recent species of
Cyrena.
In connection with this subject I may mention that three fossil
species of Corbicula from the Paris basin, which I have had
under examination, the Corbicula cuneiformis, antiqua and forbesii, have the palleal impression terminated in a sinus as in the
American species. It may be necessary to remove these species
from the old genus Corbicula and place them  in the genus proposed for the American recent species of Corbicula.
The genus Sphaerium would I think be benefited by being
divided into four genera, as follows:1. Shell solid, strive deep, beaks rounded; example, Sph. sulcatum;
Sph. solidum of-Europe.
2. Shell somewhat solid, strive light, beaks rounded; example, Sph.
rhomboideum; Sph. corneum of Europe.
3. Shell delicate and pellucid, strise not perceptible, beaks calyculate;
example, Sph. partumneium; Sph. lacustre of Europe.
4. Shell very small, delicate, transverse, strive very light, beaks calyculate; example, Sph. bahiense; Sph. africanum of South Africa.
These last proposed genera are based upon characters drawn
from the shell alone; an examination of the soft parts of the first
three proposed subdivisions is however now being made by my
friend, Mr. Edward S. Morse, of Gorham, Maine. With regard to
the fourth proposed subdivision, which I am very confident ought
to constitute a separate genus, I regret to be obliged to state, that
as yet, all my efforts to obtain alcoholic specimens of any of the
species have been unsuccessful.  The shell of the species of this




PREFACE.                        vY
group differs very materially from those of the first three, both
in size and in shape. The species of this fourth group have
hitherto been referred to the type species, the Sph. baziense, or
described as species of Pisidium; they are very widely and
abundantly distributed through Central and South America and
the West Indies, where they take the place of the species of the
three first groups, none of which are found in those regions; one
species inhabits South Africa.  It is very desirable that the soft
parts of the species of this group should be submitted to examination, and I beg to recommend myself to the good offices of
naturalists collecting in the southern portion of this continent.
I take this opportunity to acknowledge my indebtedness to
our late Mr. Cuming, of London, for his unprecedented liberality
in allowing all the specimens of Corbiculada3 of his cabinet to
cross the ocean for my inspection, affording me thereby the only
possible means of identifying many of the species described in
Europe from this country.  My thanks are also due to Monsieur Deshayes, of Paris, for specimens of many of the species
of Corbiculada from the Paris basin, by means of which I was
enabled to compare the American species with the fossil ones
of Europe. I am further under obligations to Mr. Hanley, of
London, for having determined for me a species described by him
from Central America; to iMr. Edward S. Morse for the able and
faithful manner with which he has executed the drawings on wood
inserted in the text of the monograph; to my correspondents
abroad for the material which they have furnished me for instituting comparisons, and to my American correspondents for the
assistance they have afforded me in determining the geographical
range of the Corbiculada e of America, by sending me specimens
from all parts of the country.
It is scarcely necessary to add that I have had the full use of
all the specimens of the Smithsonian Institution.
TEMPLE PRIME.
HUNTINGTON, L. I., N. Y.,
Ibecember, 1865.








TABLE OF CONTENTS.
PAGE
Preface..o                            v
Systematic list of species.....     ix
CORBICULADE.                          1
CORBICULA.....  2
Recent species....           3
Fossil species.                      3
BATISSA.                                 9
VELORITA....                            10
CYRENA.... 12
Cyrena....... 12
Anomalous species....... 27
SPJHERIU  O........ o.32
Recent species..33
Fossil species.e....58
PISIpIUM......               59
Recent species..61
Fossil species..73
Appendix.....          a..    75
Alphabetical index.....     77
(vii)








SYSTE MATIC INDEX.
PAGE                              PAGE
CORIBICULAD_ E.           1 24. Cyrena regalis, Prime.    18
25. Cyrena meridionalis, Prime.
Corbicula, MEGERLE.   2                                     19
1. Corbicula convexa, Desh.  3 26. Cyrena ordinaria, Prime.  19
2. Corbicula paranensis, Desh. 3 27. Cyrena nitidula, Desh.    20
3. Corbicula obsoleta, Desh. 4 28. Cyrena placens, EIan.        20
4. Corbicula rotunda, Prime. 4 29. Cyrena fontaineii, Orb.   21
5. Corbicula limosa, Desh.    5 30. Cyrena acuta, Prime.        21
6. Corbicula cuneata, Desh.  6 31. Cyrena mexicana, Sow.   22
7. Corbicula brasiliana, Desh. 7 32. Cyrena californica, Prime. 23
8. Corbicula perplexa, Prime. 75 33. Cyrena panamensis, Prime. 24
9. Corbicula truncata, Prime. 7 34. Cyrena recluzii, Prime.   24
10. Corbicula moreauensis,        35. Cyrena cumingii, Desh.   25
M. d H. 7 36. Cyrena isocardioides, Desh.
11. Corbicula nebrascensis,                                      25
M. 8 H. 8 37. Cyrena tumida, Prime.    26
12. Corbicula occidentalis,       38. Cyrena pullastra, 1Morch.  26
M.   H H. 8 39. Cyrena inflata, Phil.     26
13. Corbicula cytheriformis,    40. Cyrena boliviana, Phil.  27
1.. H. 9 41. Cyrena maritima, Ad.        27
42. Cyrena notabilis, Desh.   28
Cyrenra, LAMARCK.    11 43. Cyrena floridana, Conr.   28
44. Cyrena cubensis, Prime.  29
14. Cyrena caroliniensis, Lam. 12                                29
45. Cyrena salmacida, Mrl.  29
15. Cyrena sordida, Han.    13
15. Cyrena sordida,  an.  13 46. Cyrena colorata, Prime.  30
16. Cyrena radiata, Han.       13      Cyrena anomaa, Des
47. Cyrena anomala,  Desh.    30
17. Cyrena solida, Phil.      14 48. Cyrena densata, Conr.    31
4S. Cyrena densata, Conr.    31
18. Cyrena triangula, Busch.  14 49. Cyrena dakotensis, M.  H.
19. Cyrena obscura, Prime.  15                                   31
20. Cyrena insignis, Desh.    15
21. Cyrena arctata, Desh.      16      Sphaerium, ScoPOL,.   32
22. Cyrena fortis, Prime.      17 50. Spherium sulcatum, Lam. 33
23. Cyrena olivacea, Cpr.    17  51. Sphaerium aureum, Prime. 35
(ix)




X                       SYSTEMATIC INDEX.
PAGE                               PAGE
52. Spheerium solidulum, Prime.   79. Sphaerium argentinum, Orb.
36                                 52
53. Sphaerium triangulare, Say.   80. Sphaeriumbahiense, Spix. 53
36  81. Sphmrium barbadense,
54. Spheerium striatinum, Lam.                              Prime. 53
371 82. Sphaerium modioliforme,
55. Spherium stamineum, Conr.                                 Anlt. 54
38  83. Spherium meridionale,
56. Sphzerium rhomboideum,                                  Prime. 55
Say. 39  84. Sphrerium maculatum, ilil.
57. Spheerium dentatum, Hald.                                      55
40  85. Sphaerium veatleyii, Ad. 56
58. Sphaerium fabalis, Prime. 40  86. Sphaerium portoricense,
59. Spheerium  occidentale,                                 Primze. 56
Prime. 41  87. Sphaerium parvulum, Prime.
60. Spherium nobile, Gould. 41                                     57
61. Sphaerium patella, Gould. 42  88. Sphaerium viridante, M1rl. 57
62. Sphaerium vermontanum,          89. Spherium. cubense, Prime.
Prime. 42                                 58
63. Spharium emarginatum,           90. Sphaerium recticari-dinale,
Prime. 43                        i1.  H.1. 58
64. Sphaerium flavum, Prime. 43  91. Sphaerium planum, 11I. 6 H.
65. Sphaerium tumidum, Baird.                                      58
43  92. Spherium formosum,
66. Sphzerium spokani, Baird. 44              3~. ~. H. 59
67. Sphaerium elevatum, Hald.    93. Spheerium subellipticum,
44                         A1.  H. 59
68. Spheerium partumeium, Say.
45       Pisidiumn  PFEIFFER.   59
69. Spheerium jayanum, Prime.46  94. Pisidium virginicum,Bourg.
70. Sphaerium tenue, Prime.  47                                    61
71. Sphzerium transversum, Say.  95. Pisidium adamsi, Prime. 63
48  96. Pisidium oequilaterale,
72. Spherium contractum,                                    Prime. 63
Piime. 48  97. Pisidium compressum,
73. Sphaerium  securis, Prime. 49                           Prime. 64
74. Sphaerium rosaceum, Prime.   98. Pisidium variabile. Prime. 66
50  99. Pisidium nov-eboracense,
75. Sphaerium sphmericum, Alth.                             Prime. 67
50 100. Pisidium abditum, Hald. 68
76. Sphaerium  truncatum, Lins.  101. Pisidium simile, Primie.  69
51 102. Pisidium  chilense, Desh. 69
77. Sphaerium lenticula, Gould.   103. Pisidium jamaicense, Prime.
51                                 70
78. Spherium  subtransversum,  104. Pisidium pulchellum, Desh.
Prime. 52                                 70




SYSTEMATIC INDEX.                           Xi
PAGE                                PAGE
105. Pisidium  ferrugineum,         109. Pisidium ultramontanum,
Prime. 71                           Prime. 75
106. Pisidium  ventricosum,         110. Pisidium  consanguineum,
Prime. 72                            Prime. 76
107. Pisidium  rotundatum,          111. Pisidium contortum, Prime.
Prime. 72                                   73
108. Pisidium occidentale, Nc.
73








MONOGRAPH
OF
AMERICAN CORBICULAD.
FAMILY COIRBICULADE.1
Les conQues (ex parte), LAMARCK, 1809.- Cyclad es, RAFINESQUE, 1815.Les conques jfuviatiles, LAMARCK, 1818.-Veneriadw, GRAY, 1818.Cycladia, RAFINESQUE, 1818.-Les Cyclades, FERUSSAC, 1822.- Cycladine, LATREILLE, 1825. - Cyclade, FLEMING, 1828. -Cycladea, DESHAYES, 1830.-Cyrenide, GRAY, 1840.-Cycladacea, HINDS, 1844.(ygclasidae, D'ORB., 1846.-Corbiculadw, GRAY, 1847.
Animal regular, mantle with the lobes free in front and at
the base, ending in two short syphons united at their base
and sometimes to the extremity; foot triangular, compressed,
tongue shaped or cylindrical; tentacles of the mouth small,
triangular, pointed; gills broad, unequal, united behind.
Shell regular, oval or subtrigonal, covered with an epidermis; hinge with two or three teeth in each valve; lateral
teeth two, simple or striated; palleal impression simple or
with a short sinus; ligament external.
The Corbiculadme are divided into the following six genera: —
A. Cardinal teeth 3, 3, anterior of right and posterior of left valve
smallest. Shell solid.
1. Corbicula, MEGERLE, 1811.-Shell subcordate; lateral teeth compressed, subequal, finely striated.
2. Batissa, GRAY, 1852.-Shell subcordate; lateral teeth compressed, anterior very short, posterior elongate.
3. Velorita, GRAY, 1834.-Shlell cordate, triangular, thick, teeth
large, lateral very finely striated, anterior very large, regular,
hinder elongate, compressed.
4. Cyrena, LAMARCK, 1818. Shell subcordate; lateral teeth smooth,
front roundish, hinder rather compressed.
Proc. Zool. Soc. XV, 1847, 184.




2                  AMERICAN CORBICUILADBE.
B. Cardinal teeth 2, 2, moderately diverging, front of right valve and
hinder of left valve smaller; lateral teeth elongate, compressed, smooth;
of right valve double, of left valve simple. Shell thin.
5. Spharium, SCOPOLI, 1777.- Shell oblong, cordate, equilateral;
syphon of animal separate, diverging at the tip.
6. Pisidium, PFEIFFER, 1821.-Shell ovate, wedge-shaped, inequilateral, truncated behind; syphons of animal short, united to
the end.
CORBICULA, MEGERLE.'
Tellina, MULLER, 1774.- Venus, CHEMN. 1782.- Cyclas, BRUG. 1792.Corbicula, MEGERLE, 1811.-Cyrena, LAnIK. 1818. —Venulites,
SCHL. 1820.
Animal.-" Mantle, lobes free on the lower edge and in front,
united behind; edge simple, with a series of short conical beards
just within the margin; syphons two, very short, separate, contractile; apertures fringed with short crowded conical beards;
foot compressed, subquadrate, rather produced in front; body
swollen; abductor muscles large, anterior oblong, the hinder
round, subtrigonal.
"Labial tentacles 2 pair, large, broad, trigonal, equal; gills
oblong, inner pair large, the outer about half the depth of the
inner."-GRAY, MSS.
Shell oval or trigonal, subequilateral, heart-shaped; three
diverging cardinal teeth in each valve; two lateral teeth compressed, narrow, very finely striated; beaks generally broad and
not much raised; muscular impressions small, round, or elliptical;
palleal impression variable.
This genus was instituted by Megerle1 for a certain group of
fresh-water bivalves, placed by Miiller among the Tellina, and
represented by the Tellina fluminalis, fluviatilis, and fluminea.
The Corbicula differ from the Cyrena proper, in having the
lateral teeth very much elongated, narrow, both of nearly the
same size, and very finely striated.  The species of this genus are
trigonal, and are, with the exception of Corbicula woodiana,
as compared to the Cyrena, always small. The animal is similar
to that of Cyrena.
I Berliner Mag. V, 1811, 56.




POIRBSICULA.
This genus has of late years been very generally adopted by
European conchologists. We do not find any living representative of this genus on the northern portion of this continent, the.
most northern extremity to which it extends being Mazatlan.  As
yet we know of no species front the Wrest Indies, either living or
fossil; in South America, on the contrary, they seem to exist it
considerable abundance.
A peculiarity of the Corbicula  found in America, which they
share with our Cyrena, lies in the fact that the palleal impression
always terminates in a sinus, whereas in the species from other
regions it is simple.
1. Corbicula convexa, DESHAYES.-Shell orbicular, heart-shaped,
inequilateral, solid; the anterior side the shorter; beaks
tumid, rounded, opposite; lunnla indistinct, ligament     Fig. 1.
short, prominent; valves convex, the interior white;
epidermis light-green; strim irregular, delicate; three
unequal cardinal teeth, the central bifid; lateral teeth
nearly equal, narrow, delicately striated, palleal impression terminating in a small trigonal sinus.
Long..72; Lat..66; Diam..50 inch.
"   18;  1"  16;:"    13 mill.                c. convexa.
Hacb. North America, at Mazatlan, in Mexico.
(Cabinets of Cuming and Prime.)
Corbicula convexa, DESHAYES, Proc. Zool. Soc. XXII, 1854, 342.
Corbicula ventricosa, PRIME in litt.
I have never seen the original C. convexa, but have very little
doubt from the description Mr. Deshayes gives of that species,
that the shell in my cabinet, which I called C. ventricosa, is
identical with it.
This species is easily distinguished by its globular shape, which
renders it very different from all others; externally it is somewhat
similar to the young of Cyrena mexicana.
2. Corbicula paranensis, DESAYTES.-Shell small, rounded-oval,
somewhat inflated, inequilateral; anterior side short, rounded,
posterior side somewhat abrupt; beaks small, inclined towards   Fig. 2.
the anterior; valves full, strong, interior white; strive very
light, hardly visible; epidermis light-green; hinge-margin
rounded, thick; three cardinal teeth, unequal, divergent;
lateral teeth nearly equal, the anterior one a little arched,   C
finely striated; palleal impression terminating in a small sinus.




4                   AMElRICAN CORBICULAPDI.
Long..4; Lat..34; Diam..25 inch.
44  10; "   8; 8;        6 mnill.
Hab. South America, in the Parana River. (Cabinets of the British
Museum, Smithsonian Institution, and Prime.)
Cyrenaparanacensis, D'ORB. lag. de Zool. V, 1835, 44.
Cyclas paranensis, D'ORB. Voy. Amer. 1846, 567, pl. 83, f. 23-25.
Corbicula paranensis, DESHAYES, Brit. Mus. Bivalves, 1854, 231.
This small rounded species is somewhat similar in outline to
some inflated species of Sphwriunm.  It is remarkably robust for
its size, and I know of no species of the same genus to which it
has any very near affinity.   Compared with  C. co~nvexa, it is
very much smaller, less inflated, and proportionately more solid.
3. Corbicula obsoleta, DESHAYEs.-Shell oval, trigonal, oblique,
inflated, inequilateral, proportionately solid; anterior
Fig. 3.     side broad, short, obtuse; posterior side subangular;
beaks prominent, oblique; valves rather heavy; interior
bright violet; epidermis olive-green, varying in shade in
places; strise heavy and irregular; hinge-margin narrow, three cardinal teeth, small, nearly parallel to each
other; lateral teeth narrow, equal, the anterior tooth a
little curved.
~. obsoleta.
Long..70; Lat..65 inch,
"   18; "  16 mill.
Hab. South America, in Uruguay.  (Cabinet of Cuming.)
Corbiczla obsoleta, DESHAYES, Proc. Zool. XXII, 1854, 345.-Il.
Conch. IX, 1861, pl. 2, f. 4.
In outline this species offers some similarity with C. rotunda,
it is however larger and more solid.  Compared with  C. convexa it is more oblique and less inflated.
The only specimen I have seen of this species is the one in the
collection of Mr. Cuming, which he kindly lent me for examination.
4. Corbicula rotanda, PnInE.-Shell rounded-oval, somewhat
trigonal, moderately inflated, nearly equilateral; anterior side a little the
narrower, sloping from the beaks, rounded, posterior side shorter, somewhat abrupt; beaks small, raised, inclined towards the anterior; valves
rather higher than they are broad; stripe coarse; hinge thick, three ulnequal cardinal teeth; lateral teeth nearly equal, finely striated, the anterior curved,




COelBICULA.                             5
Long..37; Lat..37; Diam..25 inch.
10;  "  10;          7 mill.
]Yab. South America, in the Surinam River, Guyana.  (Cabinets of the
Academy of Natural Sciences of Philadelphia and Prime.)
Corbicula rotunda, PRIME, Pr. Acad. Nat. Sc. Ph. 1860, 80.
The only specimens I have seen of this species, those in Philadelphia and those in my own collection, are so worn that it is not
possible to form any correct idea of the color of the epidermis, nor
of the interior markings.  Compared with  C. paranensis it is
more trigonal, longer from the beaks to the basal margin, transversely less broad and more inflated.  It differs from  C. convexa
in being smaller, less rounded, higher and less inflated.
5. Corbicutla limosa, DESHAYES.-Shell transverse, ovate-ellipti.
cal, inequilateral, compressed, somewhat tumid, comparatively solid, anterior side narrower, posterior        Fig. 4.
shorter, subtruncated; striae irregular; epidermis
greenish; valves rather strong, inside white or of a
deep violet; beaks tumid, inclined towards the interior; hinge-margin broad, with three unequal teeth;
cardinal teeth diverging, the principal ones bifurcated; lateral teeth nearly equal in length, narrow,      C. limosa.
serrulated; palleal impression terminating posteriorly
in a small trigonal sinus.
Long..87; Lat..68; Diam..50 inch.
"4  22;'f  18;  I"  13 mill.
flab. South America, in the rivers of Eastern Uruguay.  (Cabinets of
the British Museum, Smithsonian Institution, Cuming and Prime.)
Tellina limosa, MATON, Trans. Linn. Soc. London, X, 1809, 325, pl. 24,
f. 8-10.
Cyrena lnimosa, GRAY, Ann. Ph. n. ser., IX, 1825, 137.
Cyrena variegata, D'ORBIGNY, Guer. Mag. V, 1835, 44.
Cyclas variegata, D'ORBIGNY, Voy. Amer., 1846, 567, pl. 82, f. 14-16.
Cyclas linosa, D'ORBIGNY (error), loc. sub. cit. 1846, pl. 82, f. 14-16.
Corbicula senmisulcata, DESHAYES, Proc. Zool. XXII, 1854, 343.
Corbicula limosa, DESHAYES, Biv. Brit. Mus. 1854, 231.
This well-marked species varies much in general appearance; 
some specimens are beautifully marked with light brown rays run.
ning from the beaks towards the basal margin, others do not exhibit these markings. The epidermis of the young shell is very




6  AMERICAN CORBICULAIDM.
smooth, at times glossy. The interior of the valves is either white
or deep violet.  Found not unfrequently.
I have.never seen an original specimen of the Tellina limosa,
but have no doubt, from an examination of the description given
of it and of its figure, that it is the Cyrena  variegata, D'Orb.
With regard to the Corbicula semisulcata, Desh,., with the habitat
New Holland, of which I have received authentic specimens from
Mr. Cuming, I can find no difference between it and the species
under examination. I am convinced that the habitat assigned to
the Corb. semisulcata is incorrect, from  the fact that it has a
sinus, a peculiarity confined to the Corbiculadw of this continent.
This species is distinct from  all other American ones of the
genus in its elliptical and compressed shape.
6. Corbicula cuneata, DESHAYES.-Shell trigonal, very inequilateral, cuneiform, anterior side short, sloping, rounded;
Fig. 5.      posterior side longer, subangular, inferior margin
slightly rounded; beaks tumid, opposite, inclined towards the anterior, often eroded; valves solid, interior orange, pink or violet; strire regular though deep;
epidermis dark blackish or brownish-green, glossy;
hinge-margin thick, three strong cardinal teeth; lateral teeth lightly striated, anterior curved, a little the
C. ouneata.   shorter; palleal impression terminating in a small
narrow sinus.
Long..78; Lat..68; Diam..50 inch.
"  20; "  17;  "   13 mill.
Hlab. South America, in the Orinoco River. (Cabinets of Jonas, Cuming, Smithsonian Institution, Jay and Prime.)
Cyrena cuneata, Jonas, Zeit. Malak. 1814, 186.-Phil. Abb. II, 1846,
77, pl. 1, f. 6;
Cyrena globulus, JONAS, in litter.
Corbicula incrassata, DESHAYES, Proc. Zool. XXII, 1854, 342.
Corbicula cuneata, DESHAYES, Biv. Brit. Mus. 1854, 231.
This is a remarkably well characterized species not likely to be
confounded with any other, the outline recalling somewhat that of
the Cyrena antiqua of the Basin of Paris.  I know of no recent
species to which it is at all allied.
I have not seen any original specimen of the Cyrena cuneata,
Jonas, but judging from the description and figure given of it in
Philippi, I have no doubt that the specimens from which this de



CORBICULA.                             7
scription was prepared, authentic Corb. incrassata, Desh., obtained from  Mr. Cuming, from  whose collection Mr. Deshayes
described this species, are identical with it.
T1. Corbicula brasiliana, DESHAYES. —C. testa trigona, subtransversa, tumidula, ineequilaterali, tenu6 et regulariter transversim striata,
epidermide viridi nitente vestita; umbonibus minimis, prominulis, oppositis; latere antico paulo breviori, supern6 rectilineo, declivi, postico parumper attenuato, rotundato; cardine angusto tridentato, altero bidentato,
dentibus minimis divergentibus, lateralibus elongatis, angustis, sub lente
exilime striatis; sinu pallii parvulo triangulari, apice acutissimo.
Hab. South America, at Para, in Brazil.  (Cabinet of the British Museul. )
Corbicula brasiliana, DESHAYES, Biv. Brit. Mus. 1854, 232.
I have not seen any specimens of this species.
FOSSIL SPECIES.
S. Corbicula truncata, PRIME.-C. testa cordata, inaequilatera,
oblique truncata; sulcis transversis, latere antico angulato.
Long..25 mill.
Hab. North America; (in the State of New York?).  (Cabinets of the
Garden of Plants in Paris and of Valenciennes.)
Cyrena truncata LAMARCK, Anim. s. vert. V, 1818, 553.
I have never seen this species, which I am inclined to believe
does not come from  New York, but more probably from  some of
the Southern  States.  Mr. Deshayes says in the Encyclopedie
Methodique, that it bears such a close resemblance to Cyre2na
czneifbrmis, that some of the valves of the two species actually
fitted into each other.
9. Corbicula moreauensis, MEEK and HAYDEN.-" Shell ovate,
nearly elliptical, compressed, extremities rounded; anterior end narrower
than the posterior, base semi-ovate, most prominent behind the middle;
beaks not much elevated, placed a little in advance of the centre; surface
marked with fine distinct lines of growth; cardinal edge rather thick, and
having under the beaks three diverging central teeth in each valve, the
anterior of which is the smallest; lateral teeth two (in the left valve)
long, parallel to the cardinal edge, and fitting into corresponding grooves
in the other valve; muscular impressions deep."
Long. 0.90; Lat. 0.66; Diam. 0.36 inch.
Hab. North America, near Moreau River, Nebraska.  Tertiary formation. (Cabinet of the Smithsonian Institution.)




8                   AMERtICAN CORBICULAD2E.
Cyrena moreauensis, M. & H. Proc. Ac. N. S. Phil. 1856, 115.
Corbicula moreauensis, M. & H. Id. Oct. 1860, 432.
"Each of the cardinal teeth has, in its upper end, a small notch
which is occupied, when the valves are closed, by a small projection between the teeth of the other valve.  The anterior lateral
tooth appears to be larger and approaches the central teeth more
nearly than the posterior.  Our specimens are generally more or
less worn, and thickly coated with firmly adhering sand.  Found
in a sand-bed, near Moreau River, associated with bones of Titanotherium?  Probably a distant outlier of the White River
bone beds."-M. & IH.
10. Corbicula nebrascensis, MEEK and HAYDEN. — " Shell ovalovate, compressed, rather thin; extremities rounded; base semi-elliptical;
beaks moderately elevated, not gibbous, placed nearly half way from the
middle to the anterior end; surface marked with fine lines of growth, occasionally rising into obscure concentric wrinkles; edge of the cardinal
border thin; cardinal teeth close under the beaks, posterior one very
oblique. "
Long. 0.6; Lat. 0.68; Diam. 0.22 inch.
Hab. North America, near Moreau River, Nebraska. Tertiary formation. (Cabinet of Smithsonian Institution.)
Cyrena intermedia, M. & H. (preoc.), Proc. Ac. N. S. Phil. 1856,
116 (not C. intermedia, Melville, 1843).
Corbicula nebrascensis, M. & H. Proc. Acad. Oct. 1860, 432.
"This species approaches some varieties of C. pisum, but is
more inequilateral, the posterior end being comparatively longer,
the beaks are also less elevated.  From  the C. moreauensis it
will be distinguished by its shorter and more rounded form, more
elevated beaks, and much thinner cardinal edge."-M. & H.
1[1. Corbtcula occidentalis, MEEK and HAYDEN.-" Shell subtriangular, very thick, rather ventricose; anterior end and base rounded,
posterior end sloping abruptly from the beaks, and ventrically subtruncate at the extremity; beaks located a little in advance of the middle,
and elevated, pointed, incurved and approximate; surface marked with
strong lines of-growth."
Long. 1; Lat. 1; Diam. 0.71 inch.
7Hab. North America, at the Bad Lands of the Judith, Nebraska. Tertiary formation. (Cabinet of the Smithsonian Institution.)
Cyrena occidentalis, M. & H. Proc. Ac. N. S. Phil. 1856, 116.
Corbicula occidenztalis, M. & 11. Id. Oct. 1860, 432.




BATISSA.                            9
"Appears to be intermediate between C. cordata of Morris and
C. antiqua, both of which are Eocene species.  From  the first it
differs in being relatively higher; its posterior end is also shorter,
and more distinctly subtruncate.  From  the latter it differs in
being less elevated, not so concave in front of the beaks, nor so
regularly arcuate on the posterior slope from the beaks to the
base.  In front it presents the same symmetrical cordate outline
common to both these species. "-M. &  I.
12. Corbicula cytheriformis, MEEI and HAYDEN.-" Shell
broad, trigonal, ovate, varying to subcircular, rather thick and strong; extremities more or less rounded, base semi-ovate, usually more prominent
before than behind the middle; dorsal outline sloping from the beaks, the
anterior slope being more abrupt than the other and slightly concave,
while the posterior is convex; beaks rather elevated, moderately gibbous,
located in advance of the middle; surface marked by fine lines of growth,
which sometimes show a very slight tendency to gather into small irregular concentric wrinkles."
Hab. North America, near the mouth of the Judith River, Nebraska.
Tertiary formation.  (Cabinet of Smithsonian Institution.)
Corbictla cytlheriformis, M. & H. Proc. Ac. N. S. Phil. 1861, 176.
BATISSA, GRAY.
Cyprina, Cyclas, Bane. 1792.- Cyrena, LAMIARCK, 1818.-Venzus,
GRAY.-Batissa, GRAY, 1852.
Animal oval, transverse; the lobes of the mantle simple or
fringed, united posteriorly; two short syphonal tubes united at
their base; foot compressed, oval, trigonal; mouth transverse,
tentacles elongate, oval, trigonal, free; gills unequal, the inner
ones larger subquadrangular, outer ones subtrigonal.
Shell oval, rounded or subtrigonal, thick, solid, hinge broad,
three unequal, divergent cardinal teeth in each valve, the posterior
tooth longest and narrowest; lateral teeth unequal, double in the
right valve, narrow  elongated, striated, anterior tooth shorter;
ligament large, prominent, thick subcylindrical; muscular impressions large, lunular or circular; palleal impression simple.
1 Ann. Mag. Nat. Hist., n. ser., IX, 1852, 34.




10                  AMERICAN CORBICULADX.
The genus Batissa was established in 1852, by Mr. Gray, for a
class of shells heretofore included under the genus Cyrena, and
represented by the Cyrena violacea. The principal differences
between the Cyrena proper and the Batissa are the following: the
Batissa have compressed serrulated lateral teeth, the ligament is
very large, rounded and prominent, the epidermis is dark and the
palleal impression always simple. The hinge of the Batissa offers
some analogy to that of the Corbicula, but is different in so far,
that the anterior lateral tooth in Batissa is always short and much
smaller than the posterior tooth.
The animal, according to Mr. Gray,l is similar to that of Cyrena.
The species of Batissa, very limited in number, are confined in
their geographical distribution to the countries and islands of the
Indian Ocean. I am not aware that as yet any have been found
in a fossil state.
This new genus does not seem to have been received with much
favor by conchologists, and more especially by those of the continent. Mr. D.eshayes adopted it in 1854,2 in describing some new
shells from the Cuming Collection, but since then3 he has changed
his views on the subject.  I was the first to bring it into notice in
this country.4
(This genus is not represented on this continent.)
VELORITA, GRAY.5
Cyrena, GRAY, 1825.-Venus, GRAY, 1828..-Velorita, GRAY, 1834.
Animal not observed.
Shell trigonal, higher than broad, heart-shaped, thick, inflated,
posteriorly angular; hinge broad, thick, three unequal cardinal
teeth, compressed, a little oblique, anterior tooth in the right
valve very short, posterior tooth in the left valve obsolete; lateral
teeth very unequal, anterior tooth thick, short, transverse, very
close to the hinge, posterior tooth elongate, lightly striated, remote from the hinge; muscular -impressions rounded, equal; palBivalves of the Brit. Mus. 1854, 234.
2 Proc. Zool. XXII, 1854, 13.
3 An. sans vert. basin de Paris, I, 1860, 484.
4 Ann. N. Y. Lyceum, Nat. Hist. VII, 1860, 112.
5 Griffith's Cuvier, 1834, pl. 31, f. v.




VELORITA-CYRENA.                       11
leal impression ending in a very short sinus; ligament short,
narrow.
This genus was established by Mr. Gray for a shell which he
had previously described under the name of Cyrena; it differs very
materially from the other genera of the family in, its exterior shape
and in the peculiar formation of the hinge. The valves are very
thick, oblong, the beaks heart-shaped, and the lunula is very distinct and convex in the centre.  The hinge is broad, it has three
cardinal teeth, all inclined obliquely towards the posterior side,
the anterior lateral tooth is very thick, prominent, and is placed
very close to and at a right angle with the anterior cardinal tooth,
the posterior lateral tooth is long, somewhat narrow, and to a certain extent similar to that of Corbicula.
Wre know of bat one species of Velorita, a recent one from
Japan, the V. cyprinoides.
Mr. Deshayes, who does not admit the validity of this genus,
has discovered in the Basin of Paris certain forms of Cyrena,
which would seem to establish a connecting link between Telorita
and Cyrena.
(This genus is not represented on this continent.)
CYRENA, LAMARCK.I
Venus, CHEMN. 1769.-Cyclas, BRUG. 1792.-Cyrena, LAtM. 1818.Cyanocyclas, FER. 1818.- Polymesoda, RAF. 1820.-M- actra,
BRONGT. 1823.-Geloina, GERAY, 1844.
Animal oval, transverse; mantle lobes free on the lower edge
and in front, united behind into two short syphons; foot large,
compressed, ovate, trigonal; tentacles elongate, ovate, trigonal;
gills unequal, the internal ones subquadrangular, the external ones
smaller, subtrigonal.
Shell oval or subtrigonal, thick, solid; three cardinal teeth in
each valve somewhat divergent; two lateral teeth, unequal, the
anterior one situated nearer the cardinal teeth; palleal impression
variable.
The genus Cyrena, as originally constituted by Lamarck, was
Lamarck, Anim. s. vert., V, 1818, 551.




12                  AMERICAN CORBICULADPE.
made to include several genera which have since been diverted
from  it —Corbicula, Batissa and Velorita.  The genus, as now
most generally received, embraces only the species of Cyrena with
simple lateral teeth.
Cyirena in a living state are found in all tropical countries.
The genus is represented at the present time in North America but
by one species; in Central and in South America the species are
numerous and bountifully distributed.  I am not aware that, outside of America, any of the so-called Marine Cyrena have been
found.  A peculiarity of the Cyrena of this continent lies in the
fact that the palleal impression is always terminated in a sinus,
whereas in those from other parts of the world it is simple.
a. CYRENsE proper.
1. Cyrena caroliniensis, LAMARCK. —Shell orbicular-trigonal,
inequilateral; margins generally roundFig. 6.            ed; beaks obtuse, oblique, often eroded;
strise very fine; epidermis rough, of a
l H )-      grayish olive-green; valves moderately
full, not heavy; interior white in adult,
pale bluish in young, occasionally with
)   markings of light violet on the margins,K!~tl  and on the hinge; hinge-margin narrow; cardinal teeth small; lateral teeth
short, obtuse; sinus very narrow, acute
at extremity.
0. earoliniensis.     Long. 1.44; Lat. 1.16; Diam..94 inch.
"    38;  "  33;   "  25 mill.
Hab. North America, in the States of Alabama and Georgia.  (Cabinets
of the British Museum, Smithsonian Institution, Cuming, Jay, Prime and
others.)
Cyclas caroliniensis, Bose, Fer. Cat. M6eth. 1807.
Cyclas caroliniana, Bose, III, 37, pl. xxiii, f. 4.
Cyrena caroliniensis, LAM. An. s. vert. V, 1818, 558.-SAY, p1. 52.
This, our most common species of Cyrena, is not very liable to
be confounded with any other; in exterior it bears some resemblance to  C. nexicana, it differs, however, in being larger,
more trigonal, the beaks are less prominent and the sinus is narrower and more acute.  The young shell is less elongated transversely and more quadrangular than the adult.




CYRENA.                             13
2. Cyrena sordida, HIANLEY.-C. testa suborbiculari, crassa, subinaequilaterali, ventricosa aut tumida; epidermide olivaceo-fucescente et
marginem ventralem convexum versus, luteo-virescente, concentrice rugulosa; margine dorsali postico, convexiusculo, deelivi; natibus erosis, satis
prominentibus; ligamento subinfosso; lunula nulla; superficie interne
albida;' dentibus lateralibus brevibus obtusis, antico magis approximato.
Long. 1.60; Lat. 1.50 inches.
Hab. Central America. (Cabinet of Hanley.)
Cyrena sorcdida, HANLEY, Proc. Zool. XII, 1844, 159.-Index Test.
Suppl. pl. xiv, f. 51.
I have not been able to identify this species.  "The link between C. caroliniensis and C. radiata, uniting the interior and
membranaceous wrinkles of the former to the general outline of
the latter. "-Hanley.
3. Cyrena radlata, HANLEY.-Shell rounded, somewhat oblique,
heart-shaped, thick, solid, inequilateral, tumid, anterior side broad,               Fig. 7.
rounded, posterior somewhat more
extended, abrupt at extremity;
beaks small, acute, approximate at
apex, entire; strin regular, epidermis light olive-green, shiny; interior
of the valves violet; hinge-margin
very much curved, thick; cardinal
teeth unequal, divergent, the posterior teeth bifid at summit; lateral
teeth unequal, the anterior tooth approximate, the posterior tooth elongated; sinus broad at mouth, acute              C. radiata.
at extremity, very short.
Long. 1.40; Lat. 1.20, Diam. 1.00inch.
"    42;  4"  39;   "    28 mill.
Hab. In Central America, at Realejo, Nicaragua.  (Cabinets of Hanley,
the British Museum, Smithsouian Institution, Sowerby, Jay and Prime.)
Cyre~na radiata, HANLEY, Proc. Zool. XII, 1844, 159.
The specimens from which this description was prepared were
identified for me by the author himself.  In some cases the epidermis of this species shows rays of a darker hue running from the
beaks to the basal margin, this feature is, however, rather the exception than the rule.  Compared with C. arctata, to which it




14                  AMERICAN CORBICULADJE.
bears great resemblance in outline, it is very much less full, transversely broader, and the epidermis is not so dark; it is very
closely allied to C. solida.  Found not unfrequently.
4. Cyrena solida, PHILIPPI.-Shell rounded, somewhat oblique,.
heart-shaped, thick, solid, inequilateral,
Fig; 8.           very much inflated; anterior side rounded,
posterior abrupt at extremity; beaks small,
acute, curved inwards, appproximate at
apex, entire; strire regular, coarse; epidermis dusky greenish-brown; interior of the
valves violet; hinge-margin curved, thick,
cardinal teeth divergent, unequal, anterior
ones bifid; lateral teeth unequal, anterior
conical approximate, posterior narrow,
elongated; sinus broad at mouth, short,
C. solida.         acute at extremity.
Long. 1.2; Lat. 1.09; Diam. 0.7 inches.
"    34;  "   31;   "    23 mill.
Hab. Nicaragua and Balize.  (Cabinets of Hanley, Smithsonian Institution and Prime.)
Cyrena solida, PHIL. Abbild. II, 1846, 78, pl. xv, f. 9.
This species is very closely allied to the C. radiala, with which
it is often confounded, it is, however, smaller, more inflated, the
strife are not so regular, the epidermis is usually darker and without polish; some specimens exhibit on the epidermis the perpendicular rays common to C. radiata and Corb. limosa.
5. Cyrena triangula, v. d. Buscu. —Shell solid, obliquely subtriangular, subequilateral, somewhat ventricose; posterior dorsal slope angular, anterior less so, ventral margin arcuate; beaks nearly central, elevated; pointed, incurved, generally perfect; exterior calcareous, comparatively smooth, covered with a light ashy-green epidermis; interior of the
valves variable, sometimes entirely violet, at others white with violet on
the margins or flesh color on the muscular impressions; hinge-margin
thick, three unequal and rather small cardinal teeth; anterior lateral
tooth short, acute, posterior elongate, compressed; sinus narrow, elongated.
Long. 2.25; Lat. 2.25 inches.
"    57;  "   57 mill.
Bab. North America, at Mazatlan, Mexico.  (Cabinets of the British
Museum, the State of New York, Cuming and Gould.)




CYRENA.                             1 5
Cyrena tricmlgula, v. d. Busci, Philip. Abbild. III, 1849, 78, pl. 2, f. 3.
Cyrena altilis, GOULD, Bost. Il. VI, 1852, 400, pl. xvi, f. 5, bis.
Cyrena varians, CARPENTER (pars), Mazatlan Shells, 1857, 115.
Cyrena 7nexicana, CARPENTER (pars), loc. sub. cit. 1857, 115.
Under the description of C. mnexicana will be found a statement of my reasons for separating these two species, which have
been confounded by Mr. Carpenter.  The C. altilis, Gould, which
I consider identical with this species, differs a little from v. d.
Busch's original type of C. triangula as figured in Philippi,
in being smaller, a little more swollen, and in having more prominent and more acute beaks; in the' main, however, it is the same
shell.
Compared with  C. radiata it is less solid, larger, more triangular, the surface is smoother and the cardinal teeth are more
delicate; it differs from  C. olivacea in being more triangular, less
elongated, more inflated, the epidermis is thinner and the cardinal
teeth are more delicate.
Mr. Reigen seems to have found this species in abundance.
6. Cyrena obscura, PRIME.-Shell subtrigonal, heart-shaped, inflated, solid, tumid, subequilateral; anterior side rounded; posterior
broader, rounded, subtruncated at extremity; beaks large, prominent,
slightly eroded; valves heavy, full, interior white with markings of violet
on the margins; strie regular, deep; epidermis blackish-brown; hingemargin curved, moderately broad; cardinal teeth unequal, divergent;
lateral teeth elongated, narrow, anterior tooth nearer the cardinal teeth,
larger, acute.
Long. 1.80; Lat. 1.70; Diam. 1.06 inches.
48;      44;   "    33 mill.
fab. South America. (Cabinet of Cuming.)
Cyrelna obscura, PRInIE, Proc. Zool. XXVIII, 1860, 321.
The only specimen I have seen of this species is the one in Mr.
Cuming's collection.  Compared with C. insignis, it is much less
inflated and more equilateral; it is fuller and transversely less
elongated than C. olivacea.'/. Cyrena  insignis, DESHAYES. - Shell ovate-cordiform, thick,
coarse, inequilateral; anterior side somewhat the shorter, broadly rounded;
posterior side broad, truncate, obtusely angular; beaks large, tumid, somrnewhat oblique, opposite, eroded; striae coarse, irregular more numerous on




16                   AMERICAN CORBICULAD:E.
the margins; epidermis dark brownish-green; hinge-margin curved; cardinal teeth strong, unequal, divergent; anterior
Fig. 9.        lateral tooth large, broad, conical; posterior lateral tooth situated at a greater distance from the
cardinal teeth, narrow, small; interior of the
valves white or pale salmon color, with at times
markings of violet on the margins; sinus very
narrow, deep, ascending in a direction oblique to
the beaks.
Long. 1.75; Lat. 1.56; Diam. 1.43 inches.
"    45;  "   40;   "    36 mill.
C. insignis. H- ab.'North America, in the State of California.
(Cabinets of Cuming and Prime.)
Cyrena insignis, DESH. Proc. Zool. XXII, 1854, 20. —Il. Conch. IX,
1861, 39, p1. 2, f. 2.
This species, which is quite rare, the only specimens known
being the one in Mr. Cuming's collection and that in mine, does
not present many points of similarity with any others.
S. Cyrena aretata, DESHAYES. -Shell trigonal, inflated, heartshaped, heavy, inequilateral; anterior side
Fig. 10.          short, somewhat angular; posterior side subtruncated; beaks large, oblique, generally
eroded; strise heavy, regular; epidermis
blackish-green; interior of the valves white
or pale rose-color with at times markings of
pale violet on the muscular impressions;
sinus short and broad; hinge-margin strong;
cardinal teeth small, simple; lateral teeth
subequal, prominent.
Long..86; Lat..86; Diam..68 inch.
C. arctata.                35;  "  35;  "   28 mill.
Flab. South America, in Lake Maracaibo. (Cabinets of Cuming, Smithsonian Institution, Jay, Swift, Bland and Prime.)
Cyrena arctata, DEst. Proc. Zool. XXII, 1854, 20.
This species, though found in great abundance in the waters of
Lake Maracaibo, has not to my knowledge been collected in other
localities.  Compared with C. radiata, to which it bears some resemblance in marginal outline, it differs in being somewhat smaller,
very much more ventricose and more solid; the beaks are larger




CYRENA.                              17
and more full and the epidermis is darker and without any perpendicular radiations.
9. Cyrena fortis, PRImE. —Shell trigonal, tumid, solid, inequilateral; anterior side shorter,
rounded; posterior side sub-                   Fig. 11.
truncated; valves moderately
full, interior dark violet; beaks
large, inclined anteriorly, approximate at apex, slightly
eroded; striw deep, regular,
epidermis shiny, varying from
green to brownish-green; hinge
margin somewhat broad, curved; cardinal teeth unequfal,
divergent,  simple;  lateral
teeth strong, anterior tooth
nearer to the cardinal teeth,
conical, posterior tooth, elongated; sinus deep, curved and
acute at extremity.
Long. 2.38;  Lat. 1.77'; 
Diam. 1.22 inches.                             a. fortis
Long. 62; Lat. 47; Diam..32 mill.
Hab. South America, in Ecuador. (Cabinets of Smithsonian Institution
and Prime.)
Cyrenafortis, PRIME, I1. Conch. IX, 1861, 355-X, 1862, 387, pl. xiv,
f. 2.
This fine and rare shell presents great similarity to C. radiata,
it differs, however, in being larger, less equilateral, transversely
longer, the beaks are a little fuller, the hinge is not so strong or
so broad and the epidermis has more lustre; the perpendicular
radiations common to some specimens of C. radiata are wanting.
10. Cyrena olivacea, CARPENTER.-Shell irregular, subtrigonal,
somewhat compressed, subequilateral anterior side shorter, rounded, posterior narrower, very angular; beaks large, prominent, inclined towards
the anterior; valves very little convex, interior violet, darker on the margins; exterior surface irregular, strine coarse; epidermis rich olive-green;
hinge-margin much curved, three unequal rather small cardinal teeth;
2




18                  AMERICAN CORBICULADXB.
anterior lateral tooth quite prominent, posterior shorter than usual; sinus
very narrow, rather straight.
Fig. 12.
C. olivacea.
Long. 2.50; Lat. 2.06; Diam. 1.25 inches.
"    63; "    52;   "    32 mill.
Hab. North America, at Mazatlan, in Mexico.  (Cabinets of the British
Museum, Smithsonian Institution, State of New York, Cuming and Prime.)
Cyrena fontaineii, PHILIPPI, Zeit. Malak. 1851, 70.-DESH. Brit.
Mus. Cat. 1854, 253.
Cyrena olivacea, CARP. Mazatlan Shells, 1857, 114.
Philippi and Deshayes have both confounded this species with
the C. fontaineii of D'Orbigny, which is a more regularly formed
shell with very regular strioe and with an even epidermis.
Mr. Carpenter, in speaking of the C. olivacea, says it is known
outwardly by its flattened form, by its rich olive-green epidermis
covering the umbos and rising into irregularly corrugated folds,
which are very close on the anterior part.  The interior displays
a very dark purple over the greater part of the surface.  The outline varies considerably.  So far this species has not been found
in any abundance.
It. Cyrena regalEis, PRIE.-Shell small, subtrigonal, subequilateral, somewhat compressed, transversely short; anterior side rounded,
posterior side forming a declivity from the beaks, somewhat produced,
subabrupt at extremity; beaks nearly central, small, not much raised,




CYaSNA.                              19
approximate at apex, eroded; strise deep, very regular; valves solid, interior light violet; epidermis light olive-green; hingemargin  slightly  curved, broad; cardinal teeth           Fig. 13.
strong, unequal, divergent, the posterior ones bifid;
lateral teeth unequal, depressed, posterior distant;
sinus irregular in shape, long and tapering at extremity.
Long. 0.76; Lat. 0.73; Diam. 0.43 inches.'6   19;   "   18;'4   10 mill.
Hab. South America? (Cabinet of Prime.)               C. regalis.
A  rare and pleasing species, the strioe are deep and very regular, which distinguish it fromn others; it is smaller, less inflated and
transversely shorter than C. solida, the posterior margin is more
produced at the extremity, the sinus is longer, the strime are more
regular and the epidermis is of a lighter color.
12. Cyrena meridionalis, PRInxT.-Shell small, subquadrangular, compressed, subequilateral; anterior side
semi-circular, a little produced; posterior side        Fig. 14.
subabrupt; beaks small, inclined anteriorly, approximate at apex, eroded; striae delicate, rather
irregular;  epidermis  light brownish-green;
valves solid, interior light violet; hinge-margin
slightly curved; cardinal teeth strong, unequal,
divergent, central tooth bifid; lateral teeth compressed, small, subequal; sinus narrow, curved
at extremity.
" nmeridionalis.
Long. 1.40; Lat. 1.32; Diam. 0.92 inches.
"    35;  "    33;   "       23 mill.
HZab. South America, at Payta, in Peru.  (Cabinet of Prime.)
The external appearance of this species brings it near C. ordinaria; it is, however, much more transverse, and the hiuge-margin is broader and less curved.  A  rare species.
13. Cyrena ordinaria, PRIME.-Shell small, trigonal, transversely
very short, compressed, subequilateral; anterior side semi-circular; posterior side rounded from the beaks downwards, subabrupt at extremity;
beaks prominent, small, inclined anteriorly, approximate, eroded; strie
fine, irregular, epidermis light brownish-green; valves solid, interior light
violet; hinge-margin curved, broad; cardinal teeth unequal, divergent,




20                   AkMERICAN CORBICULADP.
Fig. 15.        anterior tooth in the right valve rudimentary,
central slightly bifid; lateral teeth compressed,
the cavity of the anterior tooth in the right valve
united to the cardinal by a well-defined fissure;
anterior tooth approximate; sinus short, curved
at end.
Long. 0.86; Lat. 0.90; Diam. 0.53 inches.
6    21;  "   22;   6    13 mill.
C. ordinaria.      Hab. South America? (Cabinet of Prime.)
Compared with  C. regalis, it is larger, transversely shorter,
less heavy, less produced on the posterior side, fuller, the beaks
are more prominent, the strise are less regular and more delicate,
the epidermis is not so greenish in color.  Smaller and less full
than C. radiata and C. solida.  A rare species.
14. Cyrena nitideula, DESHAYES. —Shell transversely oval, fragile, inequilateral; anterior side shorter, rounded at end; posterior side
rounded or subtruncated; strine light; epidermis greenish; beaks tumid,
acute, opposite; valves light, somewhat compressed; interior pale violet;
sinus short, triangular, acute; hinge-muargin very narrow; cardinal teeth
unequal, divergent, narrow, bifid; lateral teeth subequal, small.
Long. 1.12; Lat. 1.00; Diam. 0.68 inches.,"    28; "'  25;  "    17 mill.
Hab. South America?  (Cabinet of Cuming.)
Cyrena nitidula, DESHAYES, Proc. Zool. XXII, 1854, 23.
The specimen in the collection of Mr. Cuming, from which this
description was prepared, has no Locality assigned to it; the fact
of its having a sinus places it without a doubt among the species
from America, and I am strongly inclined% to think that it is a
native of South America.
15. Cyrena placens, HANLEY.-C. testa suborbiculari, subventricosa, inoequilaterali, nitida, concentrice, sulcato-striata, epidermide irridoflavescente induta; margine ventrali convexo; dorsali, utrinque declivi et
convexiusculo; natibus erosis; ligamento fulvo, depresso, angusto; lumula
nulla; superficie interna purpurea; dentibus lateralibus minutissime
rugulosis haud autem crenatis, antico brevi et subapproximato.
Long. 1.75; Lat. 1.50 inches.
Hab. South America? (Cabinets of Hanley and the Jardin des Plantes.)
Cyrena placens, HANLEY, Proc. Zool. XII, 1844, 160.-Index test.
suppl. pl. xiv, f. 52.




CYRENA.                              21
I have not been able to identify this species, which Mr. IHanley
informs me is very rare, the shell labelled as such in the cabinet
of Mr. Cuming, he says is not the true C. placens.
"' A beautiful and rare species, of which I have never seen but
my own specimen and that in the Jardin des Plantes at Paris.
The sulci are close and regular, and the outline of the shell,
although not very unlike that of C. radiata, is convex in front
of the beaks, thus rendering the front extremity broad and somewhat obtuse." —fHanley.
I have reason to believe that this species is closely allied to
C. fontaineii.:16. Cyrena fontaineii, CABPENTER.-Shell trigonal, solid, compressed, inequilateral; anterior side short, rounded; pos-                Fig. 16.
terior narrow; acute and angular  at extremity; beaks
small, acute, eroded; strime
fine, regular, epidermis smooth,,
chestnut-brown;  interior of
the valves light-blue; hingemargin curved, thick; cardinal teeth large, unequal, divergent, the anterior ones bifid; lateral teeth unequal, anterior proximate, conical, posterior distant, elongated, compressed.                                      C. fontaineii.
Long. 1..66; Lat. 1.40; Diam. 0.80 inches.
" 41;  "    35;.   "         20 mill.
H.ab. South America.  (Cabinets of Cuming, Jay and Prime.)
Cyclcasfontaineii, D'ORB. Voy. Amer. 1844, 569, pi. 83, f. 14, 15.
cyrenafontcineii, CARP. Mazatlan Shells, 1857, 114.
Compared with C. olivacea, with which this species has been
confounded, its outline is more regular, it is smaller, more compressed, the beaks are smaller and more acute, the epidermis is
smoother and of a different color.  A rare species.
17'. Cyrrena  acut a, PRIaM. —Shell trigonal, oblique, transversely
elongated, very inequilateral, somewhat compressed, solid; anterior side
short, rounded at end; posterior side produced, angular at end; beaks tu




22                    AMERICAN CORBICULAD2R.
mid, inclined anteriorly, approximate at apex, somewhat eroded; strime
heavy, very regular; epidermis light
Fig. 17.               brown; valves thick, interior variable,
pale salmon or dark violet; hinge-margin curved, moderately broad; cardinal teeth unequal, divergent, simple;
lateral teeth elongated, subequal, posterior tooth a little more elongated
and depressed and slightly more distant from the cardinal teeth; sinus narrow, curved and acute at extremity.
Long. 1.64; Lat.  1.44; Diam.
0.88 inches.
Long. 41; Lat. 36; Diam. 22 mill.
HFab. Central America.  (Cabinet
C. acuta.              of Prime.)
Cyrena acuta, PRIME, II. Conch. IX, 1861, 355 —X,1862, 387, pl. xiv, f. 1.
A rare and fine species, easily distinguished from others by the
great prolongation of the posterior side.
1S. Cyrena mexicana, SowERBY.-Shell small, rounded oval or
elliptical, subequilateral; anterior side a litFig. 18.           tie the shorter, broader, rounded, posterior
side narrower, subangular at end; beaks medium size, somewhat raised, inclined towards
the anterior, generally eroded; valves moderately convex, interior white, with at times
purple markings on the margins and on the
j g 7;' hinge; epidermis very variable, rough or
/img F  smooth, color dingy gray or light yellowishgreen; strin generally ligLt; hinge thick,
three unequal cardinal teeth; the anterior
0. meaicana.
lateral tooth acute, short, the posterior elongated; sinus long and narrow.
Long. 1.25; Lat. 1.12; Diam. 1.18 inches.
32;               2;   "     29 mill.
Hab. North America, at Mazatlan and Panama.  Guyana?  (Cabinets
of the British Museum, Smithsonian Institution, Cuming, State of New
York, and Prime.)
Cyrena mexicana, Sown. Zool. I1. 1829, 364.-CARP. (pars) Mazatlan
Shells, 1857, 115.
Cyrena fr'aqilis, DESHAYES, Mus. Cuming.
Cyrena tqulilateralis, DESHAYES, Proc. Zool. XXII, 1854, 20.
Cyreina varians, CARPENTER, in litt.




CYRENA.                           23
This species varies very much in external appearance, being, at
times, more convex than the specimen from which this description
was prepared; I have a young C. mexicana which is quite globose.  The epidermis is usually light yellowish-green and smooth,
but in some cases it is of a dingy gray color and rough.
The original type of Mr. Sowerby's C. mexicana having been
lost, some confusion has arisen as to the identification of this species; the description he gives of it, though quite short, contains
sufficient, taking the locality into consideration, to induce me to
believe that the shell under consideration is the one he had in view
in describing his species.
Mr. Carpenter includes under the head of C. mexicana the C.
altilis, Gould, or rather the C. triangula, v. d. Busch, as it
should be called, both being identical.  I have examined an original specimen -of C. altilis, and am  convinced that it is different from  C. mexicana.  I have also examined, at the State
Collection in Albany, a complete suite of C. mexicana arranged
by Mr. Carpenter himself, and find that though at times certain
extreme forms of C. mexicana and  C. triangula bear great
affinities to each other, the two types are very distinct and may
be separated without much trouble. The C. triangula is always
more triangular, larger and more solid than C. imexicana, and
its beaks are more prominent.
The C. Jforidana, which Mr. Carpenter places under the synonymy of this species, is an entirely different shell.
I have seen original specimens of C. fragilis, Desh., and of
C. equilateralis, Desh., in the Cuming Collection, and find them
identical with C. mexicana.  The C. tquilateralis is assigned
as coming from Guyana, an error, in my opinion.  The C. mexicana is, on the whole, an attractive species; it is found quite
abundantly.
19. Cyrena californica, PRIME. -Shell ovate-subquadrangular, transverse, inequilateral, tumid, somewhat heavy; anterior side produced towards the upper part, obliquely subtruncate, posterior side broadly
truncated towards the upper part and angular towards the inferior part,
basal margin rounded; beaks not much raised, somewhat oblique, eroded;
str'ie light, irregular; epidermis yellowish-green; valves white inside with
violet on the margins; hinge-margin somewhat broad; cardinal teeth divergent, narrow, approximate at base; lateral teeth unequal; anterior tooth
thick, conical, short; posterior tooth narrow, placed at a greater distance
from the cardinal teeth.




24                  AMERICAN CORBICULADhE.
Long. 1.81; Lat. 1.56; Diam. 1.20 inches.
"    45;'    39;  "    30 mill.
Hab. North America, in the State of California, (Cabinet of Cuming.)
Cyrena subquadrata, DESH. (preoc.) Proc. Zool. XXII, 1854, 21.
Cyrena cal2forniensis, PRIME, Proc. Ac. N. S. Phil. 1860, 276.
The only specimen I have seen of this rare species is the one in
the collection of Mr. Cuming.  In shape this shell is somewhat
like that of the C. radiata, but otherwise they are widely distinct;
it is very different from all other species of the genus.
20. Cyrena panamensis, PRInE. —Shell orbicular-subtrigonal,
heart-shaped, ventricose, inequilateral; anterior side short, concave on the
upper part, produced and rounded in front; posterior side broader, obliquely truncated, obtuse at extremity; beaks large, very prominent, opposite, approximate at apex; strim light, irregular; epidermis brownishgreen; hinge-margin very narrow; cardinal teeth unequal, small, divergent; anterior lateral tooth thicker than the posterior.
Long. 2.20; Lat. 2.08; Diam. 1.68 inches.
55;  "   52;   "    42 mill.
Hab. Central America, at Panama.  (Cabinets of the British Museum
and Cuming.)
Cyrena iIJlata, DESHAYES, (preoc.) Proc. Zool. XXII, 1854, 23.
Cyrena panamensis, PRIME, Proc. Ac. N. S. Phil. 1860, 283.
A rare shell, the only specimen I have seen is the one from Air.
Cuming's collection.  Compared with C. cumningii it is smaller,
more tumid, transversely less elongated; it differs from  C. maritima in being more tumid, transversely shorter, and in having more
prominent beaks.
21. Cyrena recluzii, PRIME. —Shell heart-shaped, inflated, subequilateral, tumid; anterior side rounded; posteFig. 19.        rior side subtruncate; beaks prominent, inclined
anteriorly, approximate at apex; lunula obsolete;
strioe irregular; epidermis dark brownish-green;
valves solid, full, interior whitish; hinge-margin
curved, broad; cardinal teeth unequal, divergent,
bifid; anterior lateral tooth narrow, robust, nearer
the cardinal teeth; posterior tooth lamellar, distant.
Long. 2.96; Lat. 2.96; Diam. 2.20 inches.
"    74;  "   74;   "    55 mill.
C. recluzii.      HRab. Central America. (Cabinet of Cuming.)




CYRENA.                             e5
C(yrena cordiformis, RECLUZ, (preoc.) I1. Conch. IV, 1853, 251, pl.
vii, f. 9.
The only specimen I have seen of this species, is the one in the
cabinet of Mr. Cuming.  Mr. Recluz does not assign any locality
to it, but I am satisfied on careful inspection that it comes from
Central America.  Compared with C. inJlata, it is heavier, more
inflated and more heart-shaped.
22. Cyrena cumingii, DESHAYEs.-Shell ovate-subtrigonal, inequilateral, tumid, heart-shaped; anterior side short, broadly rounded;
posterior side longer, truncated at extremity; beaks large, prominent, opposite, approximate at apex, eroded; valves rather solid, interior white;
stris light and irregular; epidermis brownish-green; hinge-margin narrow, somewhat broad in the centre; cardinal teeth approximate, narrow,
unequal, bifid; lateral teeth large, equidistant from the cardinal teeth,
anterior tooth larger, conical, acute.
Long. 2.40; Lat. 2.08; Diam. 1.76 inches.
"    60;  "    52;   "      44 mill.
Hab. Central America. (Cabinet of Cuming.)
Cyrena cumingii, DESHAYES, Proc. Zool. XXII, 1854, 22.
A rare shell, the only specimen I have met with is the one in
Mr. Cuming's collection.  Compared with C. maritima, it differs
in having an epidermis, in being larger, transversely more elongated and less inflated.
23. Cyrena  isocardioides, DESEHAYES.-Shell orbicular-subtrigonal, inflated, heart-shaped, light, fragile; anterior side a regular and
broad semicircle; posterior side forming on the upper part a declivity,
subtruncated at extremity; striae light, irregular; epidermis olive-color
with zones of black; beaks large, curved inwards, opposite, tinted with
violet; hinge-margin very narrow; cardinal teeth very small, aplroximate,
subequal, the two anterior ones parallel, the posterior divergent; lateral
teeth small, situated at about the same distance from the cardinal teeth;
valves white inside, with markings of violet on the margins.
Long. 2.16; Lat. 2.12; Diam. 1.60 inches.
9"   54; 4"   53;   "    41 mill.
lab. South America, in Western Columbia.  (Cabinet of Cuming.)
Cyrena isocardioides, DESH. Proc. Zool. XXII, 1854, 22.
A rare species, the only specimen I have seen is the one in AMr,
Curning's collection; it presents great affinity to C. recluzii in




26                   AMERICAN CORBICULAD2E.
shape and bulk; it differs, however, in being very much less heavy
and solid; the hinge-margin is narrower and the teeth are smaller
and slighter.
24. Cyrena tumida, PRIME.-Shell trigonal, inflated, equilateral,
somewhat solid; anterior margin convex, obtuse, subangular; posterior
margin convex, presenting a declivity on the upper part, angular, subrostrated; inferior margin ventricose; epidermis dark; beaks very small,
depressed, opposite; hinge-margin narrow; cardinal teeth small, narrow,
the two larger ones bifid; lateral teeth unequal, compressed, the anterior
one large, acute, triangular; valves white in the interior with a rosy hue.
Long. 1.36; Lat. 1.20; Diam. 0.80 inches.
34;  "    30;   "    20 mill.
Hab. Central America.  (Cabinet of Cuming.)
Cyrena angulata, DESH. (preoc.) Proc. Zool. XXII, 1854, 22.
The only specimen I have seen of this species is the one in the
collection of MIr. Cuming.
25. Cyrena pullastra, MORCH.-C. testa ovalis, tennis, albescens,
radiatim subtilissime striata, valde inoequilateralis, convexiuscula, antice
brevissime angustata, postice late rotundata, margo dorsalis anticus precipite declivis, posticus rectus fere horizontalis, postice angulo obtuso;
mnargo ventralis parum  arcuatus; area postice violacea tincta; dens lateralis posticus valvne sinistrne remptissimus, compressus, inter laminas 2
valvwe dextre receptus; dens anticus subapproximatus; sinus syphonalis
angustissimus, sursum spectans.
Long. 30; Lat. 23 mill.
Hab. Central America, at Realejo in Nicaragua.  (Cabinet of Mirch.)
Cyrena (Polymesoda) pullastra, M6OcH, Malak. B1. VII, 1860, 194.)
I have not been able to identify this species.  I know  of no
Cyrena-ro'm Realejo to which the above description would apply.
26. Cyrena infiata, PILIPPI. —C. testa ovato-trigona, valde tumida, tenui, irregulariter transversim striata, epidermide olivaceo-nigrescente vestita; extremitate postica elongata; apice subtruncata; margine
ventrali parum arcuato; apicibus valde prominentibus, involutis, decorticatis; dentibus cardinis lateralibus integris, in valva dextra abrupte terminatis; pagin4 interna alba.
Long. 28f"'; Alt. 26"/'/; Crass. 21'1/.
lab. Central America, in Costa Rica.  (Cabinet of v. d. Busch.)
Cyrena ilfata, PHILIPPI, Zeit. Malak. 1851, 71.




CYRENA.                             2S
"Species forma inflata, testa telui, apicibus prominentibus ab
affinibus valde recedit, et Isocardiam  cor in mentem vocat."
I have not been able to identify this species.
217. Cyrena boliviatna, PHILIPPI.-C. testa subtrigona, valde inwequilatera, regulariter transversim  undato sulcata; epidermide olivacea
vestita, extremitate antica rotundata, postica acute angulata rostrata;
margine dorsali postico longissimo, parum arcuato; medio lunulau tumido;
apicibus integris; dentibus lateralibus abbreviatis integris; cardinalibus
integris; pagina interna violaceo-suffusa; sinu palliari distincto angusto.
Long. 16"/l; Alt. 14"/'; Crass. 8/'/.
Hab. South America, in Bolivia.  (Cabinet of Largilliert.)
Cyrena boliviaza, PHILIPPI, Zeit. Malak. 1851, 70.
I have not been able to identify this species.
b. ANOMALOUS SPECIES.
2S. Cyrena  maritima, C. B. ADAxrs.-Shell orbicular-heart.
shaped, inequilateral, solid; anterior side
short, rounded; posterior side produced, trun-        Fig. 20.
cated at extremity; beaks large, inclined anteriorly, approximate  at apex, acute, not
eroded; valves very full, whitish inside;
strire coarse, irregular; epidermis greenishbrown, worn on the upper portion of the
shell; hinge-margin narrow, not much curved; cardinal teeth small, narrow, subequal,
divergent, bifid; lateral teeth depressed, at
about the same distance from the cardinal
teeth, a small narrow indentation leads from
the anterior tooth to the cardinal teeth; sinus      C. maritima.
not distinguishable.
Long. 2.26; Lat. 1.94; Diam. 1.44 inches.
"    56;  "    48;   "       36 mill.
Hab. Central America, at Panama.  (Cabinets of Amherst College,
Cuming and Prime.)
Cyrena maritima, C. B. ADAMs, Ann. N. Y. Lyc. V, 1852, 499.
The late Professor Adams, from whom I obtained my specimen
of this species, says of it, " its station is in impalpable mud under
bushes at high-water mark where a small stream emptied; some
of the dead shells have balani growing upon them-i nine specimens
were collected at two-and-a-half miles east of Panama.'




28                   AMERICAN CORBICULADIE.
Like all the species of this genus which live in estuaries, it is
nearly entirely deprived of epidermis, some few  remnants of it
only existing on the margins of the shell.  The C. maritim.a is
very much larger than any of the so-called marine Cyrena known
to us, and is not likely to be confounded with any of them.
29. Cyrena notabilis, DESHAYES.-Shell transversely rounded,
subquadrilateral, somewhat depressed, inequilateral; anterior side short,
obtuse; posterior side broadly truncate; superior and inferior margins
straight, parallel' beaks oblique, not eroded, approximate at apex; strine
light, irregular; epidermis greenish; valves solid, interior white with a
broad patch of dark violet on the upper portion of the posterior margin;
ligament elongated, cylindrical; cardinal teeth unequal, oblique, bifid;
anterior lateral tooth small, conical, posterior tooth somewhat obsolete,
more distant from the cardinal teeth.
Long. 2.31; Lat. 1.87; Diam. 1.43 inches.
"    58;  "   48;   "       37 mill.
Hab. South America, in Peru.  (Cabinet of Cuming.)
Cyrena notabilis, DESH. Proc. Zool. XXII, 1854, 21.
Mr. Cuming possesses the only specimen I have seen of this
species, which is found at the mouths of rivers.  Compared with
C. obscura it is more quadrangular and less tumid; it differs very
materially from  C.. maritima and C. anomala, and it is much
larger and heavier than any other of the estuarian species.
30. Cyrena  foeridana, CONRAD.-Shell trigonal, inequilateral,
cuneiform; anterior side the shorter, somewhat proFig. 21.       duced, rounded; posterior side angular, subtruncate
at end, with an obtuse fold near the margin; basal
margin curved, irregular; beaks small, approximate at apex, curved inwardly, entire; lunula
somewhat marked; striae irregular, coarse especially towards the posterior margin where they
6. floridana.   assume the shape of folds; epidermis wanting;
hinge-margin very much curved; cardinal teeth
subequal, divergent; anterior lateral tooth sharp; posterior lateral tooth
narrow, elongate; valves solid, moderately inflated, exterior pale violet,
interior rough, whitish pink with dark violet bands on the margins; sinus
not visible.
Long. 1.12; Lat. 0.81; Diam. 0.48 inches.
"    28;  "   20;   "    12 mill.




CYRENA.                             29
Hcab. North America, at Tampa Bay, in the State of Florida.  (Cabinets
of Phillips and Prime.)
Cyrena floridaiia, CONRAD, Proc. Ac. N. S. Phil. III, 1846, 23, pl. 1,
f. 1,
This species has no epidermis, and presents many of the characters of a marine shell; compared with C. salmacida, which is
about of the same size, it differs in being irregular in outline, less
elongated and of a somewhat different color; it is smaller and
coarser than C. maritima, and larger than either C. colorata or
C. cubensis.
31.  yrenla ciubensis, PaRIME.-Shell small, trigonal, compressed;
anterior side short, rounded; posterior side produced, subangular; beaks
small, raised, inclined towards the anterior, not eroded; strine fine; epidermis wanting; color violet; hinge-margin broad; cardinal teeth diverging;
valves solid, interior salmon color.
Long. 0.60 inch.
"    15 mill.
flab. North America, in the Island of Cuba.  (Cabinet of?.)
Cyclas maritima, D'ORB. Moll. Cuba, II, 1853, 280, pl. xxi, f. 47-50.
This species presents the appearance of a marine shell; compared with C. floridana it is smaller and more regular in outline;
it is larger and more solid than C. colorata; it is smaller, less inflated and more highly colored than C. maritima, and smaller and
more inflated than C. salmnacida.
32. Cyrena  salmacida, MORELET.-Shell inequflateral, oval,
solid, elongated; anterior side short, rounded;
posterior elongated, subabrupt at end; beaks          Fig. 22.
small; striae irregular, not heavy; epidermis
wanting, exterior of valves whitish or fleshcolored; hinge-margin narrow; cardinal teeth
small; lateral teeth small, elongated.
Long. 1.08; Lat. 0.76 inches.
"    27;'"  19 mill.
C. saimnacida.
Hclb. Central America, near the Port of Sisal,
in Yucatan. (Cabinets'of Morelet and Cuming.)
Cyrena salmacidd, MORELET, Test. nov. Cub. pt. 2, 1851, 26.
The specimens collected by the author, which have passed
through my hands, were found in salt-water marshes.  A  rare




30                   AMERICAN CORBICULAD.E.
species.  In outline it offers some resemblance with C. colorata,
it is, however, larger, more inflated and very much more solid.
33. Cyrena colorataj PRIME. —Shell very small, fragile, elongated,
cuneiform, very inequilateral, compressed, anteFig. 23.         rior side broader, rounded; posterior side longer,
produced, subabrupt at extremity; beaks small,
acute; strise very fine, hardly visibjle; color
variable, whitish  with  zones of purple, or
orange;  epidermis  wanting;  hinge-margin
nearly straight, narrow, teeth small and delicate; cardinal teeth unequal, divergent, anterior
0. colorata.      tooth rudimentary, posterior ones bifid; lateral
teeth unequal, elongated, narrow.
Long. 0.80; Lat. 0.52; Diam. 0.28 inches.
"    20;  "    13;   "       7 mill.
fab. The WVest Indies, in the Island of New Providence.  (Cabinets of
the Smithsonian Institution, Cooper, Browne and Prime.)
The external appearance of this species presents all the character of a marine shell, its denticulation, however, places it without
a question in the genus Cyrena.  Mr. W. Cooper, of Hoboken,
its discoverer, found, several specimens of it in a brackish pond,
living in company with some Cerithia.  It is smaller, more fragile, less inflated and more regular in outline than either C. floridana) C. salmacida or C. cubensis.
34. Cyrena anomala, DESHA'ES.-Shell trigonal, very much inflated, heart-shaped, very inequilateral, strire very
Fig. 24.       fine, regular, hardly  perceptible; epidermis light
grayish-green; beaks large, acute, inclined inwards;
anterior side short, broadly semi-circular; posterior
side extended, conical, acute and angular at extremity; valves very fragile, interior grayish with
markings of violet; hinge-margin rounded, very narrow; cardinal teeth very small, approximate, subequal, divergent, the central tooth bifid; lateral teeth
C. anomala.     subequal, distant, compressed; sihus very small,
barely visible.
Long. 2.00; Lat. 1.60; Diam. 1.36 inches,
"    50;  "   40;   "    34 mill.
Hab. South America, in Peru.  (Cabinets of Cuming and Prime.)
Cyrena anomala, DESH. Proc. Zool. XXII, 1854, 21.
Cyrena peruviana, DESH. Bivalv. Brit. Mus. 1854, 257.




CYRENA.                            31
A very rare species, the only specimens I have seen being the
one in Mr. Cuming's cabinet and a young one in my own, which
was received from him.  It is easily distinguished from all others
by the peculiar outline of the posterior side which terminates in
a very acute angle.   The shell marked  C. peruviana in AMr.
Cuming's collection, from   which  Mlr. Deshayes described  it,
belongs without doubt to the species above.
FOSSIL SPECIES.
35. Cyrena densata, CONRAD.-" Shell subtriangular, thick, convex; anterior margin obtusely rounded; basal margin profoundly and
regularly curved to the posterior extremity, which is subtruncated, direct,
and greatly above the line of the base; beaks central, sunmmnits elevated;
strie robust; teeth large, robust, very prominent; middle tooth of the
right valve bifid; lateral teeth elongated, robust, anterior tooth truncated,
suddenly deflected at the extremity, posterior tooth distant."
Long. 1.87; Lat. 1.80 inches.
fab. North America, at Petersburg, in the State of Virginia. Tertiary
formation. (Cabinet of?.)
Cyrena denzsata, CONRAD, Proc. Ac. N. S. Phil. 1, 1845, 324.
36. Cyrena dakotensis, MEEK and HAYDEN.-" Shell suborbicular, or broad ovate-subtrigonal, moderately convex; anterior and posterior
sides rather abruptly rounded; base forming a semi-oval curve; dorsal
outline sloping from the beaks, the anterior slope being a little concave,
and the posterior convex in outline; beaks rather elevated and subcentral;
anterior muscular impression narrow, ovate, well defined; posterior broader
and more shallow: palleal line distinct, nearly simple, or very faintly
sinuous just beneath the posterior muscular scar; surface marked by more
or less distinct concentric striae."
Long. 1.20; Lat. 1; Diam. 0.58 inches.
Hab. North America, at the mouth of the Big Sioux or Dakotah River.
Dakotah group of the Nebraska and Dakotah cretaceous series. (Cabinet
of the Smithsonian Institution.)
Cyprina arenaria, MEEK & HAYDEN, Proc. Ac. N. S. Phil. 1857, 143.




32                  AMERICAN CORBICULADA.
SPIZJEIRIUM, SCOPOLI.1
Pectunculus, LISTER, 1685.-Musculus, GUALT. 1742. —Tellina, LINN.
1758.-Sphr riurn, ScoP. 1777.-Cardiunm, DA COSTA, 1778.-Cyclas, BRUG. 1792. —Aux, HUMPHR. 1797.-Musculium, LINK,
1807.- Cornea, Pisum, MEGERLE, 1811. — Corneocyclas, FER.
1818. —Amesoda, RAFIN. 1820.- Pisidiumn, VERANY, 1846.
Cycladites, KRUG. 1848.
Animal oval, lobes of the mantle simple, united posteriorly, and
terminating in two short syphons, joined at their base, without
tentacles; mouth oval-shaped, small; tentacles of the mouth short
and narrow; gills rather broad, nearly equal, united behind the
foot; foot narrow, elongated.
Shell oval, nearly equilateral; beaks somewhat inflated and
prominent; hinge-margin narrow, with two primary teeth in each
valve; lateral teeth elongated; palleal impression simple; ligament external, narrow, situated on the longer portion of the shell.
The genus Sphwerium was characterized under its present name
by Scopoli, in 1777; since that time, however, it has received
various denominations, and the one under which it has been most
generally known, that of Cyclas, was applied to it in 1792 by
Bruguiere.  Mr. Gray revived the term of S phrium  in 1847,
and his example has been followed by the conchologists of the continent of Europe.  I was the first in this country to discard the
name of Cyclas for that of Spheriznm.
The species composing this genus are small bivalves inhabiting
rivers, lakes, streams, and still waters; they are plentifully distributed all over the globe, but as far as present experience goes,
seem to be more abundant on the northern portion of this hemisphere than elsewhere.
The shell is transversely oval, nearly equilateral, thin, fragile,
sometimes translucent, with beaks more or less raised; its entire
surface is transversely striated and covered with a light epidermis
varying in color; the margins are rounded, obtuse or angular.
The interior of the valves is smooth and va,.ries in color; the muscular impressions are not very distinct; the posterior one is slightly' Introduct. ad. Hist. Nat. 1777, 397.




SPIH.RIUM.                          37 
the largest; the palleal impression is parallel with the basal mnargin; it is narrow and always simple.  The hinge-margin is very
variable; it is usually composed of two small teeth in each valve;
at times, however, they are single in one and double in the other,
or else single in both valves; these teeth are occasionally rudimentary, or even nearly obsolete. The lateral teeth placed on
each side of the cardinal teeth are double in the right valve and
single in the left one; the anterior lateral tooth is usually the
shorter.  The ligament is external; it is short, not very conspicuous, and is always found on the longer portion of the shell.
The animal of Spherium has a broad foot, capable of considerable extension; it uses it either to bore holes in the mud, in
which it sinks the posterior portion of the shell, or as means of
locomotion.  The syphonal tube is double and very retractile; it
is often white like the foot, but at times it is colored.
The habits of these molluscs are very similar to those of Pisidiumn, with which they are often found living.  The species of
Splheriumt are less abundant in individuals than those of Pisidiumr; they are also less generally distributed, and are more confined to certain localities than the latter.
a. BEAKS ROUNDED, NEVER TUBERCULAR.
1. Sphaeriua nl suIacatum, LAMARCK.-Animal white, tubes a
light orange color.
Shell transversely oval, nearly equi-         Fig. 25.
lateral, light in texture for its size;
posterior margin somewhat more pointed; anterior rounded, base slightly
curved; valves convex; beaks full,
raised above the outline of the shell;
posterior portion a little longer; sulcations coarse, regular; epidermis dark
chestnut-brown; interior light blue;
hinge-margin narrow, nearly a straight
line; cardinal teeth small, indistinct,
situated somewhat towards the anterior       Sph. sulcatum.
side, double in both valves, and so
placed as to assume the shape of the letter V reversed; lateral teeth on a
line with the primary teeth, large, strong and prominent.
The young is more equilateral than the adult; more compressed; it presents the shape of a quadrilateral, it is of a light lemon color, the striations
are as heavy as those of the mature shell.
3




34                  AMERICAN CORBICULAD2E.
Long. 0.68; Lat. 0.43; Diam. 0.31 inches.
Hab. North America, in the New England States, in the States of New
York, New Jersey, Pennsylvania, Ohio, Michigan, Wisconsin, Iowa, Minnesota and Alabama, and in Canada.  (Cabinets of the Academy of Natural
Sciences of Philadelphia, Smithsonian Institution, Garden of Plants in
Paris, Museum Delessert, Jay, Prime and others.)
Cyclas sulcata, LA.ARCK, An. s. vert. V, 1818, 560.
Cyclas saratogea, LAMARCK, loc. sub. cit. V, 1818, 560.
Cyclas similis, SAY, Nich. Encycl. Amer. edit. IX, 1818, pl. 1, f. 9.
Cyclas lasmanpsis, RAFINESQU1E, I1. scie. Phys. IX, 1820, 319, pl. 82,
f, 19, 20.
Cyclas solida, DEKAY, Rept. 1842, 220, pl. xxv, f. 265.
Cyclas gigantea, PRIME, BOSt. Proc. IV, 1851, 157.
Cyclas poniderosa, PRIME, loc. sub. cit. IV, 1851, 157.
Cyclas striatina, LAMARCK, Fer. in Mag. Zool. 1835.
Cyclas rhom2boidea, SAY, C. B. ADAtis, Vermont cat. 1842, 18.
This, our most common and widely distributed species, living
as it does in so many different sections of the country, presents at
times great variations in size, color and general appearance.  It
can, however, be easily recognized by its very elongated and equilateral form, an~d by the beaks which are uniformly full and convex; they are often eroded. The young is often of an uniform
light lemon color, which, as the shell matures, becomes gradually
darker from  the beaks downwards until the new shade covers the
whole surface of the shell; in certain intermediate stages of growth,
the shell is marked with a zone of yellow on the inferior margin;
the, color of the adult varies from a greenish-brown to a dark
chestnut.  The young shell has at times, owing to the variations
which exist between it and the adult, been taken for a different
species; by some it has been taken for the S. rhomboideuwm
The hinge-margin is generally straight.  I have specimens,
however, from Alabama, Pennsylvania and Rhode Island, in
which it is slightly curved.  One of the distinctive characters of
this species is that the lateral teeth are never placed at an angle
with the cardinal teeth; they are generally on a straight line with
them.
The finest specimens I have seen of the S. sulcatum were sent
to me by Mr. Ingalls, who had collected them in Washington
County, New York; they were remarkably convex, and measured
as much in length as 13 of an inch; the beaks were very full, and
much raised above the margin of the shell.




slRIeUt.                          35
This species was first described in 1818, by Lamarck, under
the names of C. sulcata and C. saratogea.  Say, in 1819; ignorant that this shell was known to conchologists, described it as
the C. similis, under which name, until very recently, it has been
most generally known.  Say also figured this species, but his
figure, I regret to say, is not correct, and would be more apt to
give one the idea of a Pisidium than of a Spheriutm.  The description by Say of the C. simrilis applies perfectly to the shell
under consideration, of which Dr. Gould has given a very good
figure in his Report on the Invertebrata of Massachusetts.
As related elsewhere,1 I had an opportunity, some years since,
while in Paris, to see Laar ck's original specimens of the C. sulcata and saratogea, at the Garden of Plants, and at the Delessert
Museum; and to convince myself by examination that they both
belonged to one species, and were identical with Say's C. similis.
2. Sphwerium  allreun, PRIME.-Animal not observed.
Shell transversely oval, slightly elongated, nearly equilateral, heavy,
convex; beaks full, raised above the outline of the shell;
anterior margin broad and rounded; posterior narrower    Fig., 26.
and somewhat angular; inferior slightly curved; hingemargin somewhat broad, curved; cardinal teeth diminutive, double, so placed together as to represent the form of
the letter V reversed, and rather wide-spread; lateral
teeth situated each one at an angle with the cardinal    S. aureum.
teeth, strong and large; sulcations deep, not very regular;
epidermis varying from a greenish-yellow to a bright gold color, slightly
lustrous; interior of the valves bluish-white.
Long. 0.56; Lat. 0.43; Diam. 0.37 inches.
Hab. North America, from  Lake Superior?  (Cabinets of Agassiz,
Smithsonian Institution and Prime.)
Cyclas aurea, PRIME, Bost. Proc. IV, 1851, 159.
This is one of our most attractive species, but also one of the
rarest. It is supposed to have been brought from Lake Superior
by the expedition which visited that region under Professor
Agassiz.  In general outline it offers some similarities with the
S. sulcatum; it is, however, a much more ponderous shell; it is
less elongated, more convex, its sulcations are not so regular, its' Notes on some American species of Cyclas, &c., by Temple Prime, the
Hague, 1857. 8vo.




36                   AAMERICAN CORBICUTLADE.
color is different, and  lastly, its hinge-margin is much more
curved.
Compared with S. solidulurn, it is more convex, more elongated, its posterior margin is broader, the hinge-margin is not so
much curved, the beaks are fuller, and the sulcations are not q iite
so heavy; the color is also different.
3. Sphrerium  solidulum, PRIME.-Animal not observed.
Shell transversely inequilateral, elongated, slightly convex: beaks full.
not very prominent; anterior margin rounded; posterior
Fig. 27.   drawn out to an angle; base slightly curved; epidermis
variable, dark chestnut or brownish-yellow, with sometimes
a yellow zone on the basal margin; sulcations coarse, irregular; interior dark blue; hinge-margin  considerably
curved; cardinal teeth double, in the shape of the letter V
S.. solidulum.
reversed; lateral teeth large; the anterior placed at an angle
with the margin; the posterior more on a continuation of the curve.
Long. 0.56; Lat. 0.43; Diam. 0.31 inches.
HLab. North America, in the States of New York, New Jersey, Ohio,
Maryland, Virginia, Indiana and Wisconsin. (Cabinets of the Academy
of Natural Sciences of Philadelphia, Smithsonian Institution, Jay and
Prime.)
Cyclas solidula, PRIME, Bost. Proc. IV. 1851, 158.
Cyclas distorta, PRIME, lo0C. sub. cit. IV, 1851, 158.
This species, which is not uncommon, was pmobably confounded
by our early conchologists with S. sulcatumz; it differs from that
species, however, in being less elongated, more inequilateral, less
convex, the hinge-margin is more curved, and the shell is more
solid.
4. Sphvarium  triangulare, SAY.-Animal not observed.
Shell transversely  oval, nearly  equilateral,
Fig. 28.        rather full, anterior margin slightly distended,
rounded, posterior somewhat abrupt, basal rounded; beaks large, full, prominent; lines of growth
regular, epidermis brownish; hinge-margin narrow, curved; cardinal teeth very distinct, assuming the shape of the letter V reversed; lateral
teeth prominent.
Long. 0.56; Lat. 0.43; Diam. 0.25 inches.
S. triangulare.
flab. North America, in Mexico.  (Cabinet of
the Academy of Natural Sciences of Philadelphia.)
Cyclas triangylaris, SAY, New Harm. Dissem. 1829, 356.




SPrHERIUM.                            37
The specimens from which I have prepared this description
were presented to the Academy of Natural Sciences of Philadelphia by Mrs. Say, as the C. triangularis, Say; they may or may
not be true representatives of Say's species.  In many points they
answer, his. description of the C. triangularis, but at the same
time I am not able to reconcile their shape, which is not more triangular than that of any other species, with the name he has
applied to the species.  Moreover, they bear a very strong resemblance to one of our Northern Sphaerium, the S. solidulum;
they differ from it, however, in being less heavily and more regularly striated, and in having more prominent beaks.
5. $phe2rilktt striatinum, LAMARCK.-                   Fig. 29.
Animal white, tubes light reddish yellow.
Shell slight, transversely elongated, somewhat
compressed, inequilateral; anterior margin rounded,
posterior distended, inferior rounded; beaks full,
not much raised; sulcations irregular, at times so
light as hardly to be seen with the naked eye, thus
giving the shell a lustrous appearance; color varying from a light greenish-yellow to a darker shade;    S. striatinum.
valves slight; interior blue; hinge-margin slightly
curved; cardinal teeth double, very small, of the same size; lateral teeth
larger, not very prominent.
Long. 0.43; Lat. 0.31; Diam. 0.25 inches.
~Hab. North America, in the States of New York, Connecticut, New Jersey, Pennsylvania, Michigan, Illinois, Ohio, Wisconsin, Alabama, Tennlessee, Iowa, in the Hell Gate River, Washington Territory, and in Canada.
(Cabinets of the Academy of Natural Sciences of Philadelphia, Smithsonian Institution, Jay, Prime, and others.)
Cyclas striatina, LAMARCK, An. s. vert. V, 1818, 560.
Cyclas elentula, SAY, N. Harm. Dissem. 1829, 2.
Cyclas cornea, LAMARCK, C. B. Adam's Cat. 1847.
Cyclas albula, PRIMIE, BOSt. Proc. IV,!851, 155.
Cyclas tenuistriata, PRIME, loc. sub. cit. IV, 1851, 156.
Cyclas acumninata, PRimIE, loc. sub. cit. IV, 1851, 158.
Cyclas inornata, PRIME, loc. sub. cit. IV, 1851, 159.
Cyclas simplex, PRIME, loc. sub. cit. IV, 1851, 159.
Cyclas rnodesta, PRIME, loc. sub. cit. IV, 1851, 159.
As may be seen by the above synonymy, I have been induced to
unite under this species several which I described as distinct in




38                  AMERICAN CORBICULADPEI
1851.  The differences existing between these shells are at times
quite marked, but in general characters they agree, and I am inclined to believe that these differences owe their origin solely to
local causes.
I had occasion some time since to convince myself of the identity
of the S. striatinum with the C. edentula of Say."
This species, which is not unplentiful in the localities where it
is found, varies much in size, color, and external appearance generally.  The shell from Connecticut is so slight, that it is nearly
translucent, and the strie are so light as to impart to it a lustrous
appearance; on- the other hand, I have  specimens from  the
Hoosack, which are quite heavy and coarsely striated; in the
main, however, they all seem to tally. The variety from Alabama,
described as the C. tenuistriata, is less distended, is fuller, and
the sulcations' are hardly perceptible.
Compared with S. solidulumn, this species is smaller, more inequilateral, less tumid, more compressed, less solid; less heavily
sulcated, and its posterior extremity is more distended.
6. Sphoerium  staminei m, CoNRAD.-Animal not observed.
Shell oval, somewhat full, inequilateral; anterior
Fig. 30.      generally abrupt; posterior slightly distended; beaks
very full and prominent, widely separate at the apex,
often eroded; epidermis dark brownish-yellow; stria
heavy; valves strong; interior blue; hinge-margin
curved; cardinal teeth double, nearly obsolete; lateral teeth distinct, strong.
Long. 0.56; Lat. 0.37; Diam. 0.31 inches.
S. stamineum.
Hab. North America, in the States of New Jersey,
Ohio, Illinois, Arkansas and Alabama. (Cabinets of the Academy of Natural Sciences of Philadelphia, Smithsonian Institution, Conrad, Jay and
Prime.)
Cyclas stamninea, CONRAD, Amer. Journ. XXV, 1834, 342, pl. 1, f. v.
Cqyclasfitscata, RAFINESQUE, Prime in Bost. Proc. IV, 1852, 281.
Cyclas bulbosa, ANTHONY, Prime in loc. sub. cit. IV, 1852, 283.
I have been induced to unite to this species the C. fuscata,
iRafinesque, which I consider as nothing more than a large variety.
f Notes on some American species of Cyclas, &c., by Temple Prime,
the Hague, 1857. 8vo.




SPILHmRIUM.                          39
The C. bulbosa, Anthony, is a little more globose than Mr. Conrad's typical specimens, but -presents no important characters of
difference.  The shells of this species found in New Jersey and in
Illinois, are larger than those from Alabama.
This species differs from  most of our North American ones by
its full and very prominent beaks.
T. Splaeriuma   rhom-boideum, SAY.-Animal, syphons reddishyellow.
Shell subglobular, rhombic-orbicular, equilateral; anterior margin truncated; posterior slightly angular; basal   Fig. 31.
nearly straight; beaks full, but not prominent; valves
slight, convex towards the beaks, gradually decreasing in
fulness towards the margins; interior blue; sulcations very
delicate; epidermis olive-green, with often a straw-colored. 7*om,
zone on the margins; young shell more compressed than the    boideum.
adult; hinge-margin nearly straight; cardinal teeth rudimentary; lateral teeth distinct, somewhat acute, not elongated.
Long. 0.50; Lat. 0.37; Diam. 0.31 inches.
Hab. North America, in the States of Vermont, Connecticut, Massachusetts, New York, Ohio, Michigan, and in Canada.  (Cabinets of the Academy of Natural Sciences of Philadelphia, Smithsonian Institution, Jay,
Prime, and others.)
Cqyclas rhomboidea, SAY, Acad. Nat. Sci. Phil. I1 II, 1822, 380.
Cyclas cornea, var. 3, LAMARcIC, An. s. vert. V, 1818, 558.
Cyclas eleyans, C. B. ADAMS, Bost. Jour. III, 1840, 330, pl. 3, f. 11.
This, the most attractive species of Sphwrium, is not easily
confounded with any other.  Up to within a few years it was
usually known among collectors under the name of C  elegans,
Adams.  I have stated elsewhere' my reasons for considering the
C. elegans as identical with Say's shell.  Though no longer rare
since 1851, when Mr. Whittemore found it in considerable abund-,ince at one place near Cambridge, Mass., this species does not
seem to be very widely distributed; it is confined to certain special localities.
I Annals of the N. Y. Lyceum, vol. vi, 1853, 66.




40                   AMERICAN CORBICULAD.E,
S. Sphaeriumi dentati m, HALDEMAN. — Animal not observed.
Shell large, ventricose, somewhat equilateral,
Fig. 32.        inferior and anterior margins rounded; posterior
somewhat angular; beaks large, well-rounded, distant, not very prominent; hinge-margin nearly
straight; cardinal teeth single, distinct; lateral
teeth not prominent; sulcations slight; epidermis
olive-green, with a dark narrow zone at some distance above the basal margin.
Long. 0.50; Lat. 0.40; Diam. 0.37 inches.
S. dentaetum.      Hab. North America, in Oregon.. (Cabinet of
the Academy of Natural Sciences of Philadelphia.)
Cyclas dentata, HALDEMAN, Proc. Acad. Nat. Sci. Phila. I, 1841, 100.
The young shell is more elongated and more heavily suleatecl
than the adult; the beaks are less large and less tumid.  This is
a well marked species, compared with S. patella, Gould, from
the same section of the country, it is found to be larger, more ventricose, the beaks are more inflated, and the color of the epidermis
is different.
The only two specimens I have seen of the S. dentatumn were
those from  which Mr. iHaldeman described the species, an adult
and a young one, which he was kind enough to lend me for study;
they are now deposited in the collection of the Academy of Natural Sciences of Philadelphia.
9. SphsareXium  fabalis, PRIME.-Animal, syphons crimson.
Shell transversely oval, compressed, nearly equilateral; anterior and
basal margins rounded; posterior margin slightly abrupt;
Fig. 33.    beaks not full, very much depressed; sulcations moderately
heavy, very regular, quite distinct; epidermis light-green,
it is, however, sometimes quite dark; in the young it is
often straw color; valves slight, interior blue; hinge-marS. fabalis.    gin very slightly curved; cardinal teeth small, assuming
the shape of the letter V reversed; lateral teeth slight; anterior tooth somewhat more elevated, both placed very nearly on a line
with the cardinal teeth.
Long. 0.56; Lat. 0.43; Diam. 0.25 inches.
Fab. North America, in the States of New York, Ohio, Illinois, Tennessee, Georgia, Virginia, Michigan and Pennsylvania.  (Cabinets of Smithsonian Institution, Jay and Prime.)
Cyclasfabalis, PRINiE, Bost. Proc. IV, 1851, 159.
Cyclas castanea, PRIME, 1OO. sub. cit. IV, 1851, 160.
OCclas sulculosa, DECHARPENTIER, MSS. 1851.




This is a very distinct species; I know of no other to which it
bears any resemblance; it is remarkable for its compressed appearance, and for the depression of its beaks.  Though pretty
widely distributed, it does not seem to be found anywhere in much
abundance.
The epidermis of the shell is at times so entirely stained with a
darkish substance, that it is with difficulty that its color can be
detected.
10. Sphkasriun  occidentale, PRIME.-Animal not observed.
Shell oval, small, pellucid, fragile, equilateral, margins
rounded; valves slight, rather convex; beaks full, round-  Fig. 34.
ed, not much raised; sulcations very fine, hardly visible;
epidermis horn color; cardinal teeth very diminutive;
lateral teeth more distinct.
Long. 0.31; Lat. 0.25; Diam. 0.18 inches.
Hab. North America, in the States of New York, Ver-   S. occidentale.
mont, Ohio, Michigan, Wisconsin, in the Hell Gate River,
Washington Territory, and in Canada.  (Cabinets of the Academy of Natural Sciences of Philadelphia, Smithsonian Institution, Jay and Prime.>
Cyclas ovalis (preoc.), PRIME, Bost. Proc. IV, 1852, 276.
Slhcerium ovale, STIMPSON, ADAMS, rec. gen. II, 1858, 450.
Sphcerium occidetaile, PRIME, Proc. Ac. N. S. Phila. 1860, 295.
This species is remarkable for its completely oval shape, which
renders it quite distinct from all others. It is found not uncommonly.   Compared with S. 2partumeium, under which name it
has at times been sent to me, it is much smaller, the margins are
more rounded, and the beaks are not so much raised.
11. Sp8 l-eiuin    nobile, GouLD.-Animal not observed.
Shell rhombic-ovate, inequilateral, moderately compressed; anterior
margin truncated, posterior more distended, basal curved;
beaks rounded, inclined towards the front, slightly tumid,    Fig. 35.
separate at apex; sulcations coarse; epidermis delicate,
light brown; valves strong, interior white; hinge-margin
nearly straight, moderately broad; cardinal teeth single,
distinct; lateral teeth moderately developed.              S. nobile.
Long. 0.50; Lat. 0.37; Diam. 0.25 inches.
Hab. North America, at San Pedro, in the State of California. (Cabinets of Gould, Smithsonian Institution and Prime.)
Cyclas nobilis, GOULD, Bost. Proc. V, 1855, 229. Atlas of U. S. Exp.
Expedit. pl. 36.




42                   AMERICAN CORBICULAD2E.
Compared with S. sulcatumn  it is slighter, less sulcated, more
compressed and less tumid.  This species is rare, the only specimens I have seen were kindly presented to me by Dr. Gould.
12. Sphlteriuml  patella, GouLD. — Animal not observed.
Shell rounded oval, lenticular, compressed, equilateral; margins generally rounded; beaks central, small, hardly raised; valves
Fig. 36.  slight, interior white; sulcations extremely fine; epidermis
light, of a yellowish-brown color; cardinal teeth very diminutive, so placed as to assume the shape of the letter V reversed;
lateral teeth not prominent, elongated.
S. patella.        Long. 0.43; Lat. 0o31; Diam. 0.18 inches.
Hab. North America, in Oregon. (Cabinets of Gould, Smithsonian Institution anll Prime.)
Cyclas patella, GouLD, Bost. Proc. III, 1850, 292. Atlas U, S. Exp.
Expedit. pi. 36.
This species is peculiar, owing to its compressed oval shape and
rounded beaks; compared with S,.fiavum  it is more oval, more
equilateral, and its beaks are less tumid.  The specimens in my
cabinet came from Dr. Gould.
13. SphaeriUmn  vermouitanum, PRIE. —Animal not observed.
Shell very oblique, tumid, inequilateral, full; anFig. 37.       terior margin abrupt, posterior drawn out to an
angle, basal slightly curved; beaks large, full, prominent, placed very much towards the anterior, in
which direction they are slightly inclined; sulcations coarse, moderately regular; epidermis light
green; ligament conspicuous; valves solid, interior
light blue; hinge-margin much curved, broad; cardinal teeth strong, representing the letter V  reS, vermontanum.
versed; lateral teeth elongated, strong.
Long. 0.56; Lat. 0.37; Diam. 0.25 inches.
Hlab. North America, in Lakes Champlain and Memphremagog, Vermont.  (Cabinets of Prime and Smithsonian Institution.)
SphlriumE vermoTntCa2n, PRIME, Proc. Ac. N. S. Plhil. 1861, 128.
Remarkable for its very oblique and tumid shape, and for the
abruptness of its anterior margin.  Compared with S. stamineum,
it is more tumid and less heavily sulcated; it is less elongated and
more tumid than the S. strialinurnm.  Quite rare.  I have neve:
seen but a few specimens of this species, which were received friom
tie late Prof. Adamls, of Amherst.




SPHA? RIUM.                          43
14. Sphaerium  emarginatum, PRIE. —Anima1 not observed.
Shell triangular, nearly equilateral, convex, tumid,
anterior and posterior margins abrupt, posterior slightly  Fig. 38.
more distended, basal margin curved; valves solid, interior white; beaks very full, prominent, nearly central;
ligament distinct; sulcations regular, not heavy.; epidermis brown, with several narrow transverse zones of
a dark color at regular intervals; hinge-margin curved;
cardinal teeth single, quite distinct; lateral teeth not
S. emarginatum.
much elongated, strong..
Long. 0.37; Lat. 0.37; Diam. 0.25 inches.
Hab. North America, in the region of Lake Superior.  (Cabinets of
Agassiz, Smithsonian Institution and Prime.)
Cyclas emarginata, PRIME, Bost. Proc. IV, 1851, 156.
The triangular and very tumid form of this species is quite
singular; it differs from S. vermontanum  in being more tumid,
fuller, in having larger beaks, and in being much less broad at
the base.  The young shell is more elongated and less tumid than
the adult. A rare species.
15. Sphaeriua   flavum, PRIME.-Animal not observed.
Shell transversely rounded, compressed, equilateral, delicate, margins generally rounded, the posterior a little dis-   Fig. 39.
tended; beaks central, not full, more or less depressed; valves
very slight, interior whitish; sulcations pretty deep, regular;
epidermis light, of a greenish-yellow color; cardinal teeth
small, in the shape of the letter V reversed; lateral teeth  S. flavum.
elongated.
Long. 0.43; Lat. 0.31; Diam. 0.18 inches.
Haub. North America, at the Sault St. Marie, Lake Superior.  (Cabinets
of Agassiz, Smithsonian Institution, Jay and Prime.)
Cyclas flava, PRIME, Bost. Proc. IV, 1851, 155.
This is a very slight and delicate species, quite distinct from
any others but S. patella, to which it bears some general resemblance from  its shape; it is, however, more compressed, less
high, and the exterior of the valves is very different, as they are
nearly smooth in Dr. Gould's shell.  Found not unplentifully in
the one locality.
16. Sphtriunm  tuBmidum, W. BAIRD.-S. testa ovato-trigona,
tumnida, olivacea, conferte transversim concentrice forte costata; umbonibus prominentibus, nec non erosis; interne ccerulescente; margine ventrali
rotundato.




4~4                  AMERICAN CORBICULADE.
Long. 0.50; Lat. 0.51 inches.
Hab. North America, at Sumass Prairie, Frazer River, British Columbia.
(Cabinet of the British Museum.)
Sphkarium tumidum, W. BAIRD, Proc. Zool. 1863, 69.
"This shell is of a tumid, swollen figure, and of an ovatetrigonal shape.   The color externally is dark olive, and it is
strongly ribbed concentrically.  The beaks are prominent, and
frequently eroded.  The inner surface is of a bluish tint.  The
ventral or lower margin is rounded."
11. Sphaeriun   spokani, W. BAIRD.-S. testa rotundato-ovata,
cornea, concentrice transversim conferte minute striata, nitida, sub lente
obsolete punctata; umbonibus rotundatis, obtusis; interne albida; margine ventrali rotundato.
Long. 0.48; Lat. 0.51 inches.
Hab. North America, in the Spokane and Kootanie Rivers, British Columbia.  (Cabinet of the British Museum.)
Spharium spolcani, W. BAIRD, Proc. Zoo]. 1863, 69.
This shell is smaller than S. tumnidunm, more rounded, and with
more obtuse beaks.  The strive or riblets are much less distinct;
the color is pale horny externally, and white internally.  It has a
shining appearance; but when examined by the lens, the surface
is seen to be indistinctly punctate.  The specimens taken from
the Spokane River are much larger than those collected in the
Kootaine.
b. BEARKS TUBERCULAR OR CALYCULATE.
18. Sphlarium  elevatuM, HALDEMIAN.-Animal not observed.
Shell ovate, orbicular, nearly spherical, cavity
Fig. 40.        large, equilateral, margins well rounded; beaks
central, slightly inclined towards the anterior,
lapping over the outline of the shell, large, tumid,
approximate, calyculate, prominent; hinge-margin slightly curved; cardinal teeth united, prominent; lateral ones elongated, large; valves very
strong, interior bluish; surface smooth, striation
light, irregular; color brownish-olive, greatly
varied by zones of a lighter shade, a zone of
S. elevaturn.    bright yellow bordering the inferior and part of
the lateral margins.
Long. 0.56; Lat. 0.50; Diam. 0.31 inches.




SPHERIUM.                           45
Hab. North America, at New Orleans, La., and in Florida and Alabaman
(Cabinets of the Academy of Natural Sciences of Philadelphia and Prime.)
Cyclas elevata, HALDEMAN, Proc. Acad. Nat. Sci. Phila. I, 1841, 53.
Cyclas pallida, DECHARPENTIER, MSS. 1851.
Remarkable for its transversely spherical shape, which renders
it distinct from all other species of this genus.  It is much more
solid than the generality of calyculate species, the valves being as
strong as those of any of the larger species of the preceding group.
C. pallida, the young of this species, is more delicate than the
adult; it is a little less transversely spherical, the strioe are lighter,
and the color is bright yellow.
Prof. ialdeman's original specimen of C. elevata, from which
this description was prepared, and which is now in the cabinet of
the Academy of Natural Sciences, though very perfect in appearance, comprised but a single valve.
This species seems to be very rare. I have never met with any
other specimens but the one in the cabinet of the Academy and
those I have in mine-two specimens of C. pallida, derived from
PeCharpentier himself, and a single valve from Florida.
Fig. 41.
S. eleratum.
19. Sphaerium  partumeiuinr   SAY.-Animal usually white,
in some varieties pink, syphonal tubes pink.
Shell rounded-oval, thin, fragile, pellucid, somewhat inflated, nearly
equilateral; anterior margin very slightly distended, rounded; posterior slightly abrupt; basal Fig. 42.
rounded; beaks central, calyculate, approximate
at apex; strie so delicate as hardly tobe visible;
epidermis glossy, of a light greenish horn color,
with at times a zone of a different shade on the
basal margin; valves delicate, moderately convex,
interior light blue; hinge-margin nearly straight, 
passing by a regular curve into the anterior margin,
S. partitmeium.
but curving suddenly behind so as to form an obtuse
angle, causing the posterior side to appear broader, thus giving the shell




406                 IAMERICAN CORBICULADE.
a somewhat rhombiform appearance; cardinal teeth strong, assuming the
shape of the letter V reversed; lateral teeth very much elongated.
The young shell is more compressed than the adult; it is usually light
yellow.
Long. 0.50; Lat. 0.43; Diam. 0.31 inches.
Hab. North America, in the States of New England, New York, New
Jersey, Wisconsin, Pennsylvania, Ohio, Michigan, South Carolina, Georgia,
Mississippi, Alabama, and Arkansas. (Cabinets of the Academy of Natural
Sciences of Philadelphia, Smithsonian Institution, Boston Society of Natural History, Garden of Plants at Paris, Agassiz, Jay and Prime.)
Cyclas parlurmeia, SAY, Acad. Nat. Sci. Phila. Jour. II, 1]S22, 380.
Cyclas cornea, var. 2, LAMARCK, An. s. Vert. V, 1818, 558.
Cyclas orbiczularia, BARRATT, American J1. XLVIII, 1845, 276.
Cyclas mirabilis, PRIME, Bost. Proc. IV, 1851, 157.
Cyclas ccerulea, PR1ME, loc. sub. cit. IV, 1851, 161.
Cyclas eburnea, ANTHONY, loc. sub. cit., IV, 1852, 279.
This species varies much according to the localities where it is
found, which accounts-in part for the number of names it has received.  C. orbicularia, of which I have authentic specimens
from  Mr. Barrat, is a genuine S. partumeiunm, without even any
local modifications of shape.  C. mirabilis, from  Georgia, is a
small form of this species, and C. ccrulea differs from  the type
iin being a little less inflated.  C. eburnea, from Arkansas, varies
from the northern S. parturmeium in being more compressed and
a little more elevated.  I do not think, however, taking the difference of localities into consideration, that these are characters
sufficient to warrant retaining C. eburnea as a distinct species.
I had an opportunity, while in Paris, to assure myself that the
variety No. 2 of C. cornea was a true S. partumeium.
This species is not only very widely distributed, but where it is
found, it occurs in large numbers.  The only one of our northern
species to which it bears much resemblance is S. truncatum, and
that is only in general outline; the S. partumeiumn is much more
inflated and transversely more broad.
20. Sphaeriumn jayanurl,  PRIME.-Animal not observed.
Shell rhombic, nearly equilateral, moderately convex, thin, fragile,
somewhat translucent, drawn up to an angle towards the hinge-margin;
anterior and posterior margins very abrupt, inferior very slightly curved;
beaks central, calyculate, approximate at apex; hinge-margin considerably shorter than the basal margin, slightly curved; cardinal teeth




SPHIIRIUM.                           47
distinct, in the shape of the letter V reversed; lateral teeth elongated;
valves delicate, interior light blue; strine hardly
visible; epidermis glossy, light greenish horn color,   Fig. 43.
with at times a zone of bright yellow on the inferior margin.
Long. 0.50; Lat. 0.43; Diam. 0.18 inches.
Hab. North America, in the region of Lake Superior? Iowa and Canada.  (Cabinets of Agassiz,
Smithsonian Institution, Jay, Garden of Plants in
Paris, and Prime.)                                    S. jayanum.
Cyclas jayensis, PRIME, Bost. Proc. IV, 1851, 157.
This attractive and rare species is easily distinguished by its
elevated shape and by its abrupt lateral margins, which give it a
somewhat triangular appearance.  It is related to S. ryckholti of
Europe, from which it differs, however, in being more inflated, its
beaks are less prominent, the shell is more elevated, and its
anterior margin is abrupt, whereas in S. ryckholti it is distended
and angular.
21. Sphariuni  tenue, PRIME. —Animal not observed.
Shell small, transversely oblong, pellucid, moderately full, subequilateral; anterior and basal margins rounded, posterior margin
subabrupt; beaks nearly central, not prominent, calyculate;   Fig. 44.
striations very fine and regular, hardly perceptible; epidermis 
glossy, light straw color; valves slight, interior straw color;
hinge-margin short, narrow, nearly straight; cardinal teeth
very diniinutive, lateral teeth small, elongated.           S. tenue.
Long. 0.18; Lat. 0.12; Diam. 0.06 inches.
Hab. North America, in the Androscoggin, Maine, and in the Upper
Mackenzie, British America.  (Cabinets of Prime and the Smithsonian
Institution.)
Cyclas tennuis, PRIME, Bost. Proc. IV, 1851, 161.
This species, the smallest one known to inhabit the United
States, was discovered some years since by Mr. Girard, from whom
I obtained my specimens. It may possibly be the young of some
species, but if so, it would be very difficult to say which; setting
aside its diminutive size, it appears to have all the characteristics of a mature shell.  In outline it seems to be allied to S.
tran.sversum; it is, however, more inflated, less elongated, and its
margins are more rounded.  At first sight, it might readily be
mistaken for a Pisidiun.




48                   AMERICAN CORBICULAD2S.
22. $phtrium   transversulm, SAY.-Animal white, syphonal
tubes pink, foot white.
Shell transversely oblong, elongated, subinequilateral, translucent; anterior side narrow; anterior margin
Fig. 45.           rounded, posterior margin subtruncate, basal very much curved; beaks
placed somewhat on the anterior side,
large, calyculate, very much raised
above the outline of the shell; striei
very delicate; epidermis greenishyellow, of a darker shade at times
on the region of beaks; valves slight,
interior bluish; hinge-margin very
nearly straight, narrow; cardinal teeth
S. transversum.        compressed, in the shape of the letter
V reversed, and very much expanded;
lateral teeth slightly elongated.
Long. 0.62; Lat. 0.43; Diam. 0.25 inches.
Bab. North America, in the States of New York, Pennsylvania, Ohio,
Kentucky, Arkansas, Alabama, and in Canada. (Cabinets of Jay, Prime
and the Smithsonian Institution.)
Cyclas transverse, SAY, New Harm. Dissem. II, 1829, 356.
Cyclas detrutncata, PRIME, Bost. Proc. IV, 1851, 155.
Cyclas gracile, PRIME, loc. sub. cit. IV, 1851, 156.
Cyclas constricta, AaTHONY, 10C. sub. cit. IV, 1852, 274.
This large and delicate species is remarkable for its very transverse shape and f6r the narrowness of the anterior extremity as
compared to the posterior. The form of the shell recalls that of
many of the small species from the West Indies and South
America.  It is found in considerable abundance.
C. detrutncata does not differ sufficiently from the type to constitute even a variety.  C. gracilis is a large variety of S. transversum; it is a little more inflated and of a darker color.  C.
constricta is nothing more than a difformed specimen of Say's
species, having a perpendicular furrow up the centre of each
valve, caused by some accident occurring to the shell during its
growth.
23. Sphl-rilvm  contraceum, PRIME.-Shell transversely oblong, inequilateral, translucent, moderately full; anterior side narrow;
anterior margin rounded; posterior margin subtluhncate; basal rounded;
beaks inclined towards the anterior, calyculate, raised above the outline




SPHAtRIUM.                           49
of the shell; striTe very delicate; epidermis greenish-yellow, somewhat
darker in the region of the beaks; valves slight, interior
bluish; hinge-margin somewhat rounded, narrow; cardinal    Fig. 46.
teeth slight, assuming the shape of the letter V reversed;
lateral teeth elongated.
Long. 0.56; Lat. 0.34; Diam. 0.21 inches.
Hab. North America, in the Big Prairie Creek and in. cncntractum.
Greer's Creek in the State of Alabama. (Cabinets of the
Smithsonian Institution, Lewis, Showalter, Wheatley, and Prime.)
Compared with S. transversum, to which this species is closely
allied, it is found to be smaller, less elongated, the beaks are
smaller, the anterior and posterior margins less disproportionate
and the hinge-margin is more rounded.
Found by Dr. Showalter, in not inconsiderable number.
24. Sphirium  securis, PRIME.-Animal pinkish, syphons of the
same color.
Shell rhombic-orbicular, ventricose, subequilateral, both sides of very
nearly the same length; anterior margin a little curved; posterior margin
abrupt, forming an obtuse angle with the hinge-margin:
basal margin much longer than the superior margin, round-   Fig. 47.
ed; beaks large, calyculate, slightly inclined towards the
anterior, very approximate at apex; valves slight, very convex, especially in the region of the umbones; strise delicate,
regular, hardly perceptible; epidermis glossy in some cases,  S. securis.
very variable in color, but generally of a greenish-horn,
at times of a brilliant yellow or straw color; hinge-margin curved, narrow;
cardinal teeth very small, united at base; lateral teeth slight, elongated,
very narrow.
Long. 0.37; Lat. 0.31; Diam. 0.25 inches.
Hab. North America, in the States of Massachusetts, Vermont, Rhode
Island, Pennsylvania, Michigan, New York, and in Canada. (Cabinets of
Jay, Lewis, Prime, and Smithsonian Institution.)
Cyclas securis, PRIME, Bost. Proc. IV, 1851, 160.-Ann. N. Y. Lyceum,
V, 1851, 218, pl. vi.
C. cardissa, PRIME, Bost. Proc. IV, 1851, 160.
C. crocea, LEWIS, loo. sub. cit. VI, 1854, 25.
Found plentifully at Cambridge, Mass. I cannot see differences
sufficient between S. securis and C. cardissa to separate them;
C. eardissa is more globose, transversely shorter, more elevated,
4




50                   AMERICAN CORDICULADAR.
but still interiuediate forms uniting the two are so frequent that
it is not possible that they should form distinct species.
0. crocea, Lewis, is a young of this species.
Compared with S. sphericum, the S. securis is more equilateral, the beaks are less tumid and less inclined, the sides are
less rounded, and the hinge-margin, is less curved.
25. Sphearium  rosace-m, PRInIE.-Animal not observed.
Shell small, rounded-oval, fragile, translucent, subequilateral, somewhat
compressed, margins generally rounded; beaks nearly cenFig. 48.   tral, slightly inclined  towards the anterior, calyculate,
f,    approximate at apex; valves very slight, a little convex
in the region of the umbones; strie  regular, hardly visible; epidermis shiny, reddish-brown; hinge-margin nearly
straight, delicate, narrow; cardinal teeth nearly obsolete,
lateral teeth slight, elongated.
Long. 0.25; Lat. 0.18; Diam. 0.15 inches.
2Hab. North America, in the Schuylkill River.  (Cabinet of Prime.)
Cyclas rosacea, PRIME, Bost. Proc. IV, 1851, 155.
This species, which is very rare, the only specimens known to
me being those in my collection, is not very liable to be confounded with others. Compared with S. occidentale, it is less
full, the beaks are more prominent and are calyculate.
26. Spphaerium  sphaericum, ANTHONY.-Animal not observed.
Shell globose, subequilateral, transversely
Fig. 49.        oval; anterior side narrow, distended, rounded;
inferior margin rounded; posterior margin subabrupt; beaks inclined towards the anterior,
large, prominent, calyculate; valves slight, very
convex, interior blue; strire fine and regular;
epidermis greenish; hinge-margin much curved;
S. sphcericum.   cardinal teeth strong, united at base and disposed in the shape of the letter V reversed;
lateral teeth prominent, very distinct, rather short.
Long. 0.31; Lat. 0.20; Diam. 0.18 inches.
Hab. North America, in the Black River, Ohio.  (Cabinets of Anthony,
Prime, and Smithsonian Institution.)
Cyclas sphkrica, ANTHONY, Bost. Proc. IV, 1852, 275.
Very rare; I have seen but few specimens of this species besides
those in Mr. Anthony's collection and in mine.  Compared with




SPIJ RIUM.                          5 I
S. rosaceum, it is less equilateral, more inflated and the margins
are less rounded.
2a. Sphaeriumni  trluncatitm, LINsLEY.-AAnimal not observed.
Shell rhombic-orbicular, lenticular, thin, pellucid, very slightly inflated,
subequilateral; anterior side narrower; anterior margin
rounded; posterior margin nearly a straight line; basal   Fig. 50.
somewhat curved; beaks central, calyculate, approximate
at apex; striwe very delicate; epidermis glossy, light greenish horn color; valves slight, very little convex; interior
light blue; hinge-margin very nearly straight; very narrow;
cardinal teeth diminutive, united at base; lateral teeth  S. trurncatum.
slight, narrow, not much elongated.
Long. 0.37; Lat. 0.31; Diam. 0.15 inches.
flab. North America, in the States of Maine, Vermont, Massachusetts,
Connecticut, Wisconsin, New York, Ohio, and in Canada. (Cabinets of
Linsley, Gould, Prime and Smithsonian Institution.)
Cyclas calyculata, C. B. ADAMS, Amer. Jour. XI, 1841, 277.
Cyclas truncata, LINSLEY, Amer. Jour. VI, 1848, 234, f. 3.
Cyclas pellucida, PRIME, Bost. Proc. IV, 1852, 277.
The specimens from which this description was prepared, the
same ones from which Dr. Gould described the original C. truncata, are precisely similar to those, the late Prof. Adams sent to
me labelled C. calyculata, from Vermont, and which I described,
in 1852, under the name of C. pellucida.  This species is undoubtedly very closely allied to S. lacustre, Firussac (C. calyculata of authors) of Europe, but still the differences are patent
enough to authorize its being retained as distinct.  Compared
with S. partumeium, the S. truncatum is less inflated, transversely
less broad, the posterior margin is more abrupt and the hinge
slighter. The young, more tumid than the adult, is of a lemon
yellow. Found not uncommonly.
28. Sphaerium  lenticula, GoULD.-Animal not observed.
Shell rhombic-orbic ular, lenticular, thin, pellucid, very
Fig. 51.
slightly inflated, nearly equilateral; anterior side narrower; anterior margin curved; posterior margin abrupt,
inferior rounded; beaks central, calyculate, approximate
at apex; stripe hardly visible; epidermis glossy, light
greenish horn color; valves delicate, a little convex
S. lenticula.
towards the region of the umbones; interior light blue;
hinge-margin nearly straight, narrow; cardinal teeth hardly visible, united
at base; lateral teeth slight, narrow, not much elongated.




5 2                 AMERICAN CORBICULAD),
Long. 0.43; Lat. 0.37; Diam. 0.18 inches.
flab. North America, in Carson and Klamath Rivers, California. (Cabinets of Gould, Anthony and Prime.)
Lucina lenticula, GOULD, Bost. Proc. III, 1850, 256.
Cyclas lenticula, GouLD, Atlas Explor. Exped. pl. 36, f. 528.
This species, of which I obtained specimens from Dr. Gould, is
so similar in nearly every respect to S. truncatum, that it is very
difficult to tell them  apart.  The valves of S. lenticula are perhaps a little more convex as they approach the region of the beaks,
and the hinge-margin a little more curved and less narrow.  The
young shell is of the same color as the adult, whereas, with S. truncatum, the young is of a lighter color.
29. Sphaerium   subtransversum, PuME.- Animal not observed.
Shell small, transversely oblong, equilateral, translucent, fragile, compressed; beaks central, large, calyculate; strine very delicate; epidermis
greenish-yellow.
Long. 0.30; Lat. 0.20; Diam. 0.10 inches.
Hab. North America, at Tabasco in Mexico.  (Cabinet of Cuming.)
Sphariunm subtransversum, PRIME, Proc. Zool. XXVIII, 1860, 322.
The only specimen I have seen of this species was sent to me
for description by Mr. Cuming.
30. Sphaerium   argentinum, D'ORnIGNaY.-Animal not observed.
Shell oval, small, translucent, compressed; anterior side short, somewhat angular, posterior side distended and truncated at the end; beaks
calyculate; strive delicate; epidermis greenish-brown; valves slight, interior bluish; cardinal teeth united, lateral teeth hardly visible.
Long. 0.31; Lat. 0.25 inches.
lab. South America, at Montevideo at the base of the Cerro, (Cabinet
of the British Museum.)
Cyclas argentina, D'ORBIGmY, Mag. de Zool. 1835.-IB. Voy. en Amer.
M6rid. 1844, 568, pl. 83, f. 5-7.
It has not been my good fortune to meet with this species.
M. D'Orbigny says it bears some resemblance to C. calyculata,
meaning thereby, I presume, the shell now known to Europeari
Conchologists under the name of S. lacustre, FBrussac.




SPIZERIUM.                           53
c. SHELL ALWAYS SMALL, RHOMBOIDAL, BEAKS CALYCULATE.
31.  phelriuim  bahliense, SPIx.-Animal not observed.
Shell very small, rounded-oval, inflated, inequilateral; anterior margin narrow, curved; posterior     Fig. 52.
margin broad, subtruncate; inferior margin curved;
beaks inclined towards the anterior, large, prominent,'calyculate; valves slight, interior dark yellow, irregularly mottled with dark reddish spots; lines of growth
very fine; epidermis yellowish-brown, with irregular
spots of dark purple; hinge-margin very narrow,        S. bahiense.
nearly straight; cardinal teeth small; lateral teeth
comparatively strong, the posterior one much the longer.
Long. 0.15; Lat. 0.12; Diam. 0.09 inches.
Hab. South America, at Bahia in Brazil.  (Cabinets of Jay, Prime and
others.)
Cyclas bahiensis, SPIX, Test. Braz. 1827, 32, pl. xxv, f. 5, 6.
Cyclas rmaculata, ANTON (non MORELET), Wiegm. Archiv, 1837, 284.
Pisum maculatum, DESHAYES, Brit. Mus. Cat. 1854, 283.
Pisum bahie?2se, DESHAYES, 1oC. sub. cit. 1854, 284.
Musculium bahiense, ADAMS, Rec. Gen. II, 1858, 451.
Musculiunz maculatnm,'ADAMIS, loc. sub. cit. II, 1858, 451.
This, the smallest species of Slhaerium, has the peculiar appearance characteristic of the West Indian and South American shells
of this genus.  It does not seem to be uncommon.  Some authors,
led away by its diminutive size, have committed the error, as may
be seen by the above synonymy, of placing it under the head of
Pisidium.  I have never seen C. maculata, Anton (non Morelet), but have every reason to believe, from  the description given
of it, that it does not differ materially from this species.  In outline it is somewhat similar to S. barbadense; it is, however,
much smaller, less inflated, and the beaks are much more raised.
Compared with S. mneridionale, and S. maculatum of Morelet, it
is smaller, more inflated, and the margins are more rounded.
32. Sphwerium  barbadense, PRIME.-Animal not observed.
Shell small, rounded-oval, ventricose, subequilateral, delicate; anterior
side. a little the shorter and narrower; margins generally rounded; beaks
slightly inclined towards the anterior, nearly central, small, calyculate,
approximate at apex, at times eroded; striTe coarse for the size of the




54                   AMERICAN CORBICIULADiE.
Fig. 53.     shell, though not very distinct; epidermis dark greenish-l
brown; valves slight, very convex; cardinal teeth very
small; lateral teeth strong, very much drawn up and
shorter than they usually are in other species.
Long. 0.25; Lat. 0.20; Diam. 0.15 inches.
Hab. Barbados, West Indies.  (Cabinet of Prime.)
S. barbadense.       Sphaerium barbadense, PRIME, Proc. Acad. Nat. Sci.
Phila. 1861, 415.
I have but one specimen of this species, which seems to be
closely allied to S. bahiense;: it is, however, much larger, more
globose, and its beaks are not as much raised.
33. Splhaerinm  modioliforme, ANToN.-Animal not observed.
Shell small, ovate oblong, moderately inflated, inequilateral, translucent;
anterior and basal margins rounded, posterior somewhat distended and
subtruncate; beaks inclined towards the anterior, prominent, calyculate;
valves slight, convex; epidermis dark yellow, irregularly spotted with a
darker color; striwe hardly visible; teeth very small; liinge-margin somewhat curved, very narrow.
Long. 0.31; Lat. 0.18; Diam. 0.15 inches.
Hab. South America, in Brazil and Venezuela. (Cabinets of the Academy
of Natural Sciences of Philadelphia, Bourguignat, Gassies, Museum of Paris,
Michaud, and Museum at Leyden.)
Cyclas modioliformis, ANTON, Wiegm. Archiv, 1837, 284.
Pisidium diaphanum, HALDEMAN, Proc. Acad. Nat. Sci. Phila. I,
1841, 53.
Pisum modioliforme, DESHAYES, Brit. Mus. Cat. 1854, 283.
Pisidiu n moquinianum, BOURGUIGNAT, Amen. I, 1855, 61, pl. 3, f. 13-17.
Cyclas maoquiniana, GASSIEr, Pisid. 1855, f. 9.
Cyclas striatella, FERUSSSAC, Museum of Paris.
Cyclas littoralis, FERussAc, Collect. Michaud.
Cyclas venezuelensis, PRIME, Museum of Leyden.
Musculium 2modioliforme, ADAMiS, Rec. Gen. II, 1858, 451.
The specimen from  which this description was prepared (the
original shell from which Mr. Haldeman described the P. diaphanum) is in the Cabinet of the Academy of Natural Sciences of
Philadelphia; it was discovered in the interior of a large
Ampullaria from Brazil.  I have never seen C. modioliformis or
P. moquinianum, but judging from  their descriptions and from
the figure of the latter, I do not doubt that they belong to this
species.  I have had occasion to examine C. striatella and C.
littoralis personally.




SPH-aRIUIM.                          55
S. modioliforme seems to be rare. It bears some resemblance
to S. meridionale, but it differs from it in being more inflated and
the color is lighter.
34. Sphaerilum  meridionale, PRIME.-Animal not observed.
Shell small, transversely-oblong, compressed, delicate, inequilateral;
anterior side narrow, shorter; anterior margin somewhat angular, posterior subabrupt, basal slightly       Fig. 54.
rounded; beaks inclined towards the anterior, small,
ualyculate, approximate at apex; valves slight, compressed, striae very regular and delicate, hardly perceptible;  epidermis yellowish-brown, irregularly
mottled with large blotches of ~ much darker color;
hinge-margin very slightly rounded, narrow, much
shorter than the basal margin; cardinal teeth di-    S. meridionale.
minutive; lateral teeth slight, the posterior tooth
much the more elongated.
Long. 0.33; Lat. 0.20; Diam. 0.12 inches.
Hab. North America, at Panama.  (Cabinets of Prime and Smithsonian
Institution.)
Sphzrium 7neridionale, PRIME, Proc. Acad. Nat. Sci. Phila. 1861, 414.
This species is easily distinguished by its very inequilateral
and compressed shape. Compared with S. maculatum, it is larger,
its posterior margin is less abrupt, and its lateral teeth are larger.
35. Sphaerium  maculatum, MORELET.-Animal not observed.
Shell small, transversely-oblong, rhombic, elongated, inequilateral, compressed, delicate; anterior side much the narrower,
slightly rounded; posterior side very broad; posterior   Fig. 55.
margin abrupt, forming a straight line from the hinge
to the base of the shell; inferior margin  nearly
straight; valves slight, very little convex; beaks
small, calyculate, inclined towards the anterior side;
striae not perceptible; epidermis dark yellowish-brown,
irregularly mottled with spots of a much darker color;    S. maculatum.
hinge-margin nearly straight; cardinal teeth very
small; lateral teeth strong, elongated.
Long. 0.25; Lat. 0.18; Diam. 0.12 inches.
Hub. North America, in Yucatan.  (Cabinets of Morelet, Jay, Prime
and Smithsonian Institution.)
Cyclas maculata, MORELET, Test. nov. Insul. Cub. etc. 1851, 25, pt. 2(1.
A rare species; the only specimens I have met with were




56                   AMERICAN CORBICULADA}E.
kindly presented to me by the original describer. It is easily
distinguished from  all other species of Spherium  by the very
great disproportion which exists between the lateral margins.
36. Sphoeriuml   veatleyii, C. B. ADAMS.-Animal not observed.
Shell small, transversely elongated, inequilateral, compressed; anterior
and inferior margins rounded; posterior margin subFig. 56.       truncate; beaks situated towards the anterior side
and inclined in that direction, small, prominent,
calyculate; valves slight, interior irregularly spotted
with dark blotches; striee regular, coarse for the
size of the shell; epidermis horn color with a tinge
of brown; hinge-margin nearly straight; cardinal
S. veatIeyii.   teeth small but distinct, placed in the shape of the
letter V reversed; lateral teeth well developed,
elongated.
Long. 0.18; Lat. 0.12; Diam. 0.06 inches.,Hab. North America, in the Island of Jamaica. (Cabinets of Jay and
Prime.)
Cyclas veatleyii, C. B. ADAMS, Contrib. Conch. 1849, 44.
Pisidium veatleyii, PETIT, Journ. Conch. II, 1851, 421.
Pisum. veatleyii, DESHAYES, Brit. Mus. Cat. 1854, 283.
Mliusculium veatleyii, ADAMS, Rec. Gen. II, 1858, 452.
This rare species, of which I received specimens from the late
Prof. Adams, is somewhat allied to S. portoricense; it is, however, smaller, more delicate, more elongated, the valves are less
full, the beaks less large, and the hinge is more slight.
3:. Sphaerium  portoricense, PRIME. —Animal not observed.
Shell small, transversely elongated, rhombic, equiFig. 57.      lateral, slightly compressed; margins generally straight,
in especial the posterior margin; beaks central, slightly
inclined towards the anterior side, calyculate, approximate at apex; striae regular, quite heavy with respect
to the size of the shell; epidermis light brownishyellow; cardinal teeth strong; lateral teeth strong,
short; valves solid, very little convex; the interior,
S. portoricense.    and at times the exterior, irregularly spotted with a few
dots of very dark color.
Long. 0.25; Lat. 0.20; Diam. 0.12 inches.
Hab. Portorico, West Indies. (Cabinets of Swift and Prime.)
Sphuriumn portoricense, PRIME, Proc. Acad. Nat. Sci. Phila. 1861, 415.




SPHlERIUM.                           57
The specimens from which this description was prepared were
kindly furnished to me by Mr. Swift, of St. Thomas.  In proportion to its size this species is quite robust.  It is different from
the generality of the West Indian and South American S2jphria
by its sulcations, which are regular and deep.  In shape and
appearance it recalls the young of S. sulcatumo  It is allied to
S. veatleyii in outline, but otherwise it differs, being heavier
and of a larger size.
3S. Sphaerium  parvulum, PRIME.-Animal not observed.
Shell small, transversely-oblong, inequilateral, moderately compressed; beaks calyculate, prominent; anterior    Fig. 58.
side narrower, rounded; posterior subtruncate; striue very
delicate; epidermis greenish-gray; teeth slight, but well
marked.
Long. 0.15; Lat. 0.11; Diam. 0.06 inches.         S. parulurm.
"    3f;  "    23;         1  mill.
Hlab. At Hamacao in the Island of Portorico, West Indies.  (Cabinets
of Smithsonian Institution, Morelet and Prime.)
In outline this species offers some resemblance to S. bahiense,
it is, however, much less inflated.
39. Sphaerium  viridante, MoRELET.-Animal not observed.
Shell small, transversely-oblong, compressed, delicate, inequilateral;
anterior side somewhat narrow, shorter, rounded; posterior
subabrupt, basal margin slightly rounded; beaks inclined    Fig. 59.
towards the anterior, very small, calyculate, approximate at
apex; valves slightly compressed; strin very regular and
delicate; epidermis greenish-brown, irregularly mottled with
large blotches of a darker color; hinge margin  nearly  S. viidante.
straight; cardinal teeth diminutive; lateral teeth slight,
posterior tooth longer.
Long. 0.24; Lat. 0.18; Diam. 0.13 inches.
"4   6~' "    41;  "       3- mill.
Hfab. At Pointe-a-Pitre in the Island of Guadeloupe, West Indies. (Cabinets of Smithsonian Institution, Morelet and Prime.)
The specimens from which this description was prepared were
obtained from  the author.  This species is very closely allied to
S. Mneridionale; it differs, however, in being transversely less
long, less produced at the posterior; it is also less compressed.
Found not unplentifully.




58 VAMERICAN CORBICULADiE.
40. Splherium  c-ube-nse, PRxIE. —Animal not observed.
Shell small, transversely-oblong, very inequilateral, comFig. 60.    pressed; anterior side shorter, narrower, rounded; posterior
broad, subtruncate; inferior margin very much curved;
beaks small, not much raised; striae barely visible, epidermis brownish-yellow with spots of a darker color.
S. czubease.       Long. 0.16; Lat. 0.10; Diam. 0.09 inches.
"      4;  "   2};  "       21 mill.
Hab. Sta. Catalina de Guantanamo, Punta de la Jaula and Esperanza,
Cuba, West Indies (fide Wright).  (Cabinets of Smithsonian Institution,
Wright, Morelet, Wheatley, and Prime.)
Compared with S. viridanle, this species is much smaller and
more compressed.
FOSSIL SPECIES.
41. Splaeriuia  recticardiamle, MEEK and HAYDEN. —" Shell
of medium size, transversely subelliptical, rather compressed, very thin;
anterior side rounded; base forming a regular semielliptic curve; posterior
extremity obliquely subtruncate above and rather narrowly rounded below;
cardinal margin long and straight; beaks very small, compressed and projecting but slightly above the hinge, located nearly half way between the
middle and the anterior end; surface marked by moderately distinct,
irregular lines of growth."
Long. 0.55; Lat. 0.36; Diam. 0.24 inches.
fab. Near the mouth of Grand River, on the Upper Missouri, Nebraska,
United States of America. Tertiary formation. (Cabinet of Smithsonian
Institution.)
Sphlriuin recticardinale, MEEK and HAYDEN, Proc. Acad. Nat. Sci.
Phila. 1860, 176.
42. Sphltriuni  pllanuln, MEEK and HAYDEN.-" Shell rather
small, broad oval or subcircular, much compressed; extremities more or,
less regularly rounded, the posterior margin being sometimes faintly subtruncate; base semioval in outline; cardinal margin rounding gradually
from near the middle; beaks very small, compressed, and scarcely extending beyond the hinge-margin, nearly central; surface marked by fine,
irregular, obscure concentric strim."
Long. 0.38; Lat. 0.32; Diam. 0.08 inches.
Hab. Near the mouth of Grand River, on the Upper Missouri, Nebraska,
United States of America. Tertiary formation. (Cabinet of Smithsonian
Institution.)
Sphzrianum planum, MEE:K and HAYDEN, Proc. Acad. Nat. Sci. Phila.
1860, 175.




PISIDIUM.                           59
43. Sphwrium  formosum, MEEK and HAYDEN.-" Shell small,
oval, oblique, scarcely ventricose; cardinal margin straight; buccal end
rounded; anal extremity obliquely truncate; basal margin semielliptical
or broadly rounded; beaks obtuse, tumid, rising somewhat above the
hinge, nearly touching, placed a little in advance of the middle; surface
ornamented by very fine, regular, distinct, concentric wrinkles."
Long. 0.17; Lat. 0.08; Diam. 0.14 inches.
Hab. Three miles above Fort Union, Nebraska, United States of America.
Tertiary formation.  (Cabinet of Smithsonian Institution.)
Cyclas formTosa, MEEK and HAYDEN, Proc. Acad. Nat. Sci. Phila.
1856, 115.
Cyclas fragilis, MEEK and HAYDEN, loc. sub. cit. 1856, 115.
/Spohrium formosum, MEEK and HAYDEN, ib. May, 1860, 185.
44. Sphaerium  subellipticum, MEEK and HAYDEN.-" Shell
small, elliptical-ovate, somewhat ventricose, thin and fragile; posterior
end narrower than the anterior, both narrowly rounded; base semielliptical or semiovate; cardinal border apparently rounding gradually to
both extremities; beaks not much elevated, pointed, incurved, not oblique,
located near the middle; surface indistinctly marked with lines of growth."
Long. 0.24; Lat. 0.14 inches.
Hab. Three miles above Fort Union, Nebraska, United States of America.
Tertiary formation.  (Cabinet of Smithsonian Institution.)
Cyclas subelliptica, MEEK and HAYDEN, Proc. Acad. Nat. Sci. Phila.
1856, 115.
Sphlerium subellipticumn, MEEK and HAYDEN, ib. May, 1860, 185.
" The beaks are so near the middle, and curved so nearly at
right angles to the longitudinal diameter of the shell, that it is
not easy to determine, especially from the examination of mutilated specimens, which is the posterior or which the anterior end.
As we have only seen imperfect specimens, we are not sure the
surface markings are indistinct on unworn shells."-_M. & H.
PISIDIUMl, PFEIFFER. 1
Pectunculus,. LIST. 1685.-Mutsculus, GAULT. 1742.-Tellina, MULLER,
1774.-Spheriumn., ScoP. 1777. —CarCdium, POLI, 1791. —Cyclas,
LAMK. 1818.-.Pera, Eluglesia, Cordula, LEACH, 1820.-Phlysemoda,
RAF. 1820. —Plsidium, PF. 1821.-GallilWja, DA COSTA, 1839. —
Pisum, GRAY. (non MEGERLE), 1847. —JMutsculihn?, GRAY (non
LINK), 1851.
Animal elongate-oval, compressed laterally; lobes of the
mantle without tentacles, united posteriorly into a single, short
J Pfeiffer, Deiitsch. moll. 1821.




60                AMERICAN CORBICULAD~.
syphonal tube; oral aperture small, tentacles of the mouth triangular, elongated; gills of medium  size; foot small, tongueshaped, capable of great extension.
Shell small, rounded-oval, inequilateral, anterior side longer;
beaks terminal; cardinal teeth double, at times united, situated
immediately under the beaks; lateral teeth elongated, lamelliform, double in the right valve, single in the left valve; ligament
always on the shorter side.
This genus was instituted by Pfeiffer for a class of shells which,
by the older authors, had been confounded with Tellina, and more
recently with Sphweriurn.  The differences which exist between
Pisidium and Sphterium, which led Pfeiffer to establish this new
genus, are very material, both in the animal and in the shell. The
animal of Pisidiurn has the lobes of the mantle united posteriorly
into one syphonal tube; whereas in Spohwrium, the lobes form a
tube, single at its base, but double at the extremity.  According
to M. Deshayes there is much difference in the formation of the
foot of Pisidium  from that of Sphtriunm-that of the former
being somewhat similar to that of Cardium.  This organ is
capable of great extension, and when prolonged to its utmost
extent, is not unlike that of Lucina; it is made use of much
in the same manner as that of Sphwrium, either to burrow into
the ground or to crawl on solid bodies.
With regard to the shell, the main difference consists in the
position of the beaks. In Pisidium the beaks are terminal, that
is, the distance from the beaks to the anterior extremity is greater
than the distance from the beakls to the posterior extremity.  In
Sphltrium, on the contrary, the position of the beaks is generally
central, dividing the hinge-margin into equal portions.  The
formation of the hinge of Pisidium is very similar to that of
Sphxriurm; the position of the cardinal teeth, however, in Pisidium is terminal, like that of the beaks, whereas in Sphw-rium it
is central.  The teeth of Pisidiumn are, in proportion to the size
of the shell, more robust than in Sph7rrium.
The habits and mode of living of the species of these two genera
are very much the same. They are found buried an inch or more
in the mud under water, or else attached to the roots or stems of
aquatic plants.




PISIDIUM.                         61
Their mode of breeding is much the same, both ejecting the
young when sufficiently mature, which up to that time they carry
between the folds of the gills.  Pfeiffer supposes the Pisidium to
breed by throwing out eggs, but I have myself found young in
the shells of Pisidium.
The most appropriate time of the year for collecting Pisidium,
in the North, would seem to be from the middle of April to the
early part of July-the season during which they breed; some
species, however, such as P. variabile, I have found at all seasons,
even in winter; others, such as P. ventricosum, are seldom found
but in the early summer. Live specimens may be preserved for
examination, for some time, if the water is kept sufficiently fresh.
On the application of water, slightly warmed, they exhibit great
activity, extending their syphonal tube and foot.  They not only
crawl on the sides of the vessel, in which they are confined, but
also on the under surface of the water. They are very similar in
some of their movements to certain species of fluviatile Gasteropods.
While this genus has of late years been generally adopted by
the Conchologists of Europe, and more recently by those of this
country, some English authors have committed the error of applying to it the names of Pisum and Musculium —a great carelessness on their part, as the types of these two genera, as set out
by their respective describers, Megerle and Link, are genuine
Spheria.
The genus Pisidium is very abundantly distributed over both
sections of this continent; and while the species of America are
entirely distinct as such from those found elsewhere, their forms
present, in nearly every instance, great analogies with those of
the species of Europe and of Asia.
1. Pi;sidium  virginicum, BOUrRGUIGNA. -Shell large, thick,
oblique, very inequilateral; anterior side longer, narrower, rounded; posterior broader, subtruncate at end,  Fig. 61.
basal margin rounded; beaks situated posteriorly, large,
prominent; valves solid, moderately convex, interior   1
light blue; stripe coarse and irregular; epidermis green-    -
ish-brown or chestnut color, with zones; hinge-margin
very much curved; hinge broad, two strong cardinal
teeth, disposed in the shape of the letter V reversed;
lateral teeth strong, short.
Long. 0.35; Lat. 0.29; Diam. 0.21 inches.




62                  AMERICAN CORBTCULADAE.
7Hal. North America, in New England, in the States of New York, New
Jersey, Pennsylvania, Ohio, Wisconsin, Michigan, Maryland and Virginia,
and in the St. Charles River at Quebec in Canada. (Cabinets of the Boston Society, the Academy of Natural Sciences of Philadelphia, Smithsonian
Institution, Jay, Prime, and others.)
Tellina virginica, GML., 178S, 3236, pl. clix, f. 15.
Tellina pusilla (pars), DILLW. II, 1817, 106.
Cyclas dubia, SAY, Nich. Encycl. 3d ed. 1819, f. 4, p1. i, f. x.
Physenzoda aequalis, RAFINESQUE, Ann. Gen. Sci. Phy. V, 1820, 319.
Pisidiurn abrupturnm, HALDEMAN, Proc. Acad. Nat. Sci. Phila. I, 1841, 53.
Pisiditum dubiumn, HALDEMAN, loc. sub. cit. I, 1841, 103.
Pisidium wquale, RAFINESQUE, Prime in Bost. Jour. VI, 1852, 367.
Pisdium virginicum, BOURGUIGNAT, Amer. Malac. I, 1853, 53.
Spheriumn dubiunm, DESHAYES, Biv. Brit. Mus. 1854, 266.
Pisum virginicuil, DESHAYES, loc. sub. cit. 1854, 281.
Pisum abruiptum, DESHAYES, 1OC. sub. cit. 1854, 281.
Pisum dubiumn, DESHAYES, loc. sub. cit. 1854, 282.
AMuscclium dubium, ADAMs, Rec. Gen. II, 1858, 451.
Ml~usculium abritptum, ADAMS, loc. sub. cit. II, 1858, 451.
Mfusculium virginicum, ADAMS, loc. sub. cit. II, 1858, 452.
This, the largest species of the genus found in America, is not
easily confounded with any other-its size, and general robust
and coarse appearance, rendering it at once distinct.  The young
shell is more elongated and less full than the adult, and of a
lighter color.  Found not unplentifully in running waters.
Compared with P. adamsi, to which it bears some resemblance
in outline, it is larger, more robust, more produced on the anterior
side, less full, the beaks are larger, the markings on the surface
are heavier, and the color is darker.
Its foreign analogue is P. amnicum, of Europe, to which it
is very closely allied; it differs, however, in being somewhat
smaller and more oblique.
Fig. 62.
P. vrginicuTum




PISIDIUJ.                           63
2. Pisiduitu   ada.ms4, PrIME.' —Shell subovate, full, oblique, inequilateral; anterior side a little longer, narrower, slightly
produced at end; posterior side broader, somewhat sub-    Fig. 63.
truncate at end, basal margin rounded; beaks small, a
little raised, approximate at apex; surface smooth, strive
very delicate; color light gray, interior whitish; hingemargin curved; cardinal teeth very small; lateral teeth   P. adamsi.
very distinct.
Long. 0.3; Lat. 0.24; Diam. 0.2 inches.
Hab. North America, at Norway in the State of Maine, and at Holly,
Oakland Co., Michigan.  (Cabinets of the Boston Society, Smithsonian
Institution, and Prime.)
Cyclas nitida, MIGHELS (non HANLEY), Bost. Proc. I, 1841, 48.
Pisidium adamsi, PRIME, Stimp. Moll. New Engl. 1851, 16.
Spherium nitidum, DESHAYEs, Biv. Brit. Mus. Cat. 1854, 271.
A rare species. I have never seen any specimens but those in
the collection of the Boston Society and those in my own. all of
which came from  Professor Adams, who discovered it with Dr.
Mighels.   The young is elliptical, obliquely striate and compressed. The so-called Cyclas nitida, from Connecticut and New
Hampshire, is P. variabile.
Compared with P. variabile, this species is larger, comparatively more delicate, less oblique, less heavily striated, of a lighter
color.  It is much more oblique and less elongated than P.
abditumr.  It is more oblique, and more inflated than P. virginicum; it is also more delicate than that species.
Fig. 64.
P. ada.nsi.
3. Pisidiutim  aequllaterale, PRIrE.-Shell small, stout, heavy,
somewhat inflated, rhomboidal, subequilateral; posterior margin a little'Not to be confounded with Pisumt adacmsi of DESHAYEs, Biv. Brit. Mus.
1854, 284, which is the P. janaicense, PRIME.




64                  AMERICAN CORBICULADAE.
angular where it meets the basal margin; inferior and anterior margins
slightly rounded; beaks central, large, prominent, roundet,
Fig. 65.   not approximate; valves very solid, moderately convex, interior light blue; strie fine, surface glossy, epidermis very
variable in color, light yellow, greenish or brown; hingemargin curved, cardinal teeth small, lateral teeth strong,
distinct.
P. eqeuitaterale.
Long. 0.15; Lat. 0.14; Diam. 0.10 inches.
Hah. North America, in the States of Maine, Massachusetts and New
York.  (Cabinets of the Boston Society, Smithsonian Institution, Lewis,
Jay, and Prime.)
Pisidium aquilaterale, PRIME, Bost. Jour. VI, 1852, 366, pl. xii, f. 23-25.
This species is remarkable for its solidity and for its short and
quadrangular form, the latter gives it somewhat the appearance
of a Sphwriuzm; it is the most equilateral Pisidium  I know of.
Compared with P. variabile, to which at first sight it bears a
general resemblance from the gloss and color of its epidermis, it
differs very materially in not being at all oblique, and in being
equilateral; it is also much less full.  Somewhat rare.  I discovered it in the spring of 1852, in a clay pit in the neighborhood of Augusta, Maine, in company with P. compressum.
Fig. 66.
P. cquilaterale.
4. Pisidium  compressum, PRIME.-Shell solid, very oblique,
trigonal, triangular, subequilateral, very much
Fig. 67.         drawn up in the region of the beaks, inflated
in adult; anterior side a little longer, narrower,
produced at the end, posterior broader, subtruncate; beaks placed a little posteriorly,
small, raised, with a wing-shaped appendage
on the summits, distant; strine distinct, regular; epidermis very variable, yellow, gray or
chestnut color; valves solid, varying in inflation, interior light blue; hinge thick; cardinal
P. compressum.     teeth small, robust, compressed, disposed in
the shape of the letter V reversed; lateral
teeth distinct, short, strong, placed at an obtuse angle with the hinge proper.




PISIDIUM.                           C 5
Long. 0.16; Lat. 0.14; Diam. 0.09 inches.
Hab. North America, in New England, in the States of New York, Pennsylvania, Ohio, and California, and at Montreal and Quebec in Canada.
(Cabinets of the Boston Society, Smithsonian Institution, Jay, Prime, and
others )
Cyclas altilis, ANTHONY, in litt., 1847.
Pisidium conpressutn, PRIME, Bost. Proc. IV, 1851, 164.
Pisidium altile, ANTH. Prime, Bost. Jour. VI, 1852, 353, pl. xi, f. 10-12.
Pisidiurn cicer, PRIME, Ann. N. Y. Lye. VI, 1853, 65, pl. i, f. 1.
Pisum cornpressurn, DESHAYES, Biv. Brit. Mus. 1854, 282.
Pisum altile, DESHIAYES, loc. sub. cit. 1854, 280.
Mu usculium conmlressum, ADANIS, Rec. Gen. II, 1858, 451.
MIusculiuml altile, ADAMS, loc. sub. cit. II, 1858, 451.
2lusculium cicer, ADAMS, loc. sub. cit. II, 1858, 451.
Pisum cicer, ADAMs, loc. sub. cit. II, 1858, 660.
This species, though perfectly distinct and well characterized,
is subject to much variation; its very oblique shape is constant;
in fulness it is exposed to much change, some old specimens are
remarkably obese; the young are generally more elongated and
more compressed.
One of the peculiarities of this species, which, however, is at
times wanting, from  abrasion or from  other causes, is the very
singular shape of the apex of the beaks, which assume the appearance of wings placed on the summit of the umbos.
P. cicer, from  Greenwich, which I place with this species,
differs a little from  the type of P. compressurm, in being larger,
more inflated; the beaks also are larger, and do not exhibit the
winged appendage. P. altile, a mere variety, is more oblique
than the type, and does not possess the appendage on the beaks.
Both these varieties are darker in color than the true P. cornpressunm.
The foreign analogue, P. conicurz, from  France, is so closely
allied to our species that it is with the greatest care only that
they may be separated.
P. compressumn  is more trigonal and less inflated than P.
variabile; it is more equilateral than either P. virginicunn,
adanmsi, or abditumn, and more oblique and less equilateral than
P. qauilaterale.
The animal is remarkable for its liveliness. It is found sparingly
5




66.AMERICAN CORBICULADIE.
during the spring, and not at all in winter. It inhabits both
running and still water, and buries itself somewhat in the mud.
Fig. 68.
P. compressum.;5. Pisidium    a.riabile, PRIME.-Shell heavy, oblique, inequilateral, inflated; anterior side longer, narrower, somewhat angular at end;
posterior subtruncate; beaks situated posFig. 69.          teriorly, full, prominent, not approximate
at apex; valves solid, interior light blue;
strie regular, but very distinct; epidermis
glossy, very variable, straw color or greenish-brown with a yellow zone on the basal
margin; hinge-margin curved; hinge rather
slight; cardinal teeth united, small; lateral
teeth distinct, strong, short.
Long. 0.21; Lat. 0.18; Diam. 0.17 inches.
P. qvariabile.        Hab. North America, in New England,
and in the States of New York, Pennsylvania, and Virginia.  (Cabinets of Jay, Smithsonian Institution, Prime,
and others.)
Cyclas nitida, MIGHELs, Linsley, Amer. Jour. XLVIII, 1845, 276.
Pisidium variabile, PRIME, Bost. Proc. IV, 1851, 163.
Pisidium grande, WHITTEAMORE, in litt. 1855.
Mliusculium variabile, ADAnMS, Rec. Gen. II, 1858, 452.
Pisum variabile, ADAIS, loc. sab. cit. II, 1858, 660.
This species has hitherto always been looked upon by collectors
as the P. virginicum; but having' compared it with the original
shells, described as Cyclas dubia, Say, by Dr. Gould, in his Report, and with some specimens of P. virginicum  from Westfield,
MIass., sent to me by Prof. C. B. Adams, as well as with some
others sent to me from Philadelphia, by Prof. S. S. IHaldeman, I
have become convinced that it is different from Say's shell.
Compared with the young of P. virginicun, it is more oblique,
less elongated, more inflated, and of a different color.   This
species is not so elongated as the P. virginicum; it is more inflated, the beaks are larger and more tumid, it is also a  naueic




PISIDIIUM.                           C,
smaller shell.  Say describes Cyclas dubia as being six-twentieths
of an inch in length; P. variabile is only four-twentieths of anl
inch in length, and that it is a full grown shell, I am led to believe not only from its heavy striations and mature appearance in
general, but also from  having found young in the shell.  The
young is not so oblique as the adult, it is more elongated, less
inflated, and of a light yellow color. As a general rule, the
coloring of this species varies much in different localities.  The
specimens collected from  Rowley, Essex  County, Mass., are
larger than any I have seen from other places; their color is also
lighter.  The animal is remarkable for its want of activity.  This
is one of our most common species, being found in nearly every
stream, and at all seasons of the year, though most plentifully
during the spring.
Fig. 70.
P. variabile.
6. Pisidivum   nov-e'boracense, PRIME.-Shell rounded-oval,
very inequilateral, inflated, margins rounded; anterior
side considerably produced, narrower; beaks situated      Fig. 71.
posteriorly, large, full, prominent; valves comparatively
slight, interior light blue; strip irregular; epidermis
variable, generally greenish-yellow  or brown; hingemargin a little curved; hinge slight, narrow; cardinal
teeth double, very small; lateral teeth elongated.
Long. 0.35; Lat. 0.18; Diam. 0.13 inches.
Hab. North America, in the State of New York.  (Cabinets of Smithsonian Institution, Lewis, Jay, and Prime.)
Pisidium nov-eboracense, PRInIE, Ann. N. Y. Lye. VI, 1853, 66, pl. i, f. 3.
Pisidium ampturn, INGALLs in Iitt. 1855.
Musculimon nov-eboracense, ADAIMS, Rec. Gen. II, 1858, 451.
Pisum nov-eboracense, ADAMS, loc. sub. cit. II, 1858, 660.
This species, for its size, is comparatively delicate.  It seems
to be intermediate between P. abditum  and P. variabile; it is
less elongated and more tumid than the former, and less oblique
and more elongated than the latter. Found only in two places,
at Greenwich and at Mohawk, in the State of New York.




C68                   AMERICAN C011BICULADATE.' P. Pisidium   abditun    HlALDEMIAN.-Shell rounded-oval, elnngated, very inequilateral, moderately convex,
Fig. 72.          margins well rounded, beaks placed nearer the
posterior side, small, slightly raised; surface
smooth, strise not distinct, epidermis variable,
generally light straw color; hinge-margin very
nearly straight; cardinal teeth small, separate,
the anterior tooth larger and more prominent;
lateral teeth small, not much elongated.
Long. 0.15; Lat. 0.14; Diam. 0.09 inches.
P. abditum.
Htab. North America, in New England, in the
States of New York, New Jersey, Pennsylvania, Ohio, Michigan, South
Carolina and California, in the Lake Superior region, at Montreal in
Canada, and in Honduras.  (Cabinets of Jay, Cuming, Prime, Smithsonian Institution, and others.)
Pisidium abditum, HALDEMAN, Proc. Acad. Nat. Sci. Phila. I, 1841, 53.
Cyclas minor, C. B. ADAMS, Bost. Proc. I, 1841, 48.
Pisidium tenellum, GOULD, Agassiz, Lake Super. 1848, 245.
Pisidium obscurum, PRIME, Bost. Proc. IV, 1851, 161.
Pisidium rubellum, PRIME, lo0. sub. cit. IV, 1851, 163.
Pisidium mninus, STIMPSON, Moll. New Engl. 1851, 16.
Pisidium kulrtzi, PRIME, Bost. Proc. IV, 1851, 162.
iPisidium zoatunm, PRIME, loC. sub. cit. IV, 1851, 162.
Pisidium regulare, PRIME, Bost. Jour. VI, 1852, 363, pl. xii, f. 11, 112
Pisidium notatum, PsIME, loC. sub. cit. VI, 1852, 365, pl. xii, f. 20-22.
Pisidium arcuatum, PRIME, loC. sub. cit. VI, 1852, 364, p1. xii,. 14-16,
Pisuim abditum, DESHAYES, Brit. Mus. Cat. 1854, 282.
Pisum minus, DESHAYES, loc. sub. cit. 1854, 281.
Pisidium resartum, INGALLS, in litt. 1855.
Pisidium rubrum, LEWIS, in litt. 1855.
Pisidium plenum, LEWIS, in litt. e1855.
Musculium abditum, ADAMS, Rec. Gen. II, 1858, 451.
Musculium minus, ADAMS, loc. sub. cit. II, 1858, 451.
Miusculium rubellum, ADAMS, ioc. sub. cat. II, 1858, 452.
Mlusculium obscurum, ADAMS, loc. sub. cit. II, 1858, 452.
Musculium kurtzi, ADAMS, loc. sub. cit. II, 1858, 451.
MHisculium zonatum, ADADMS, loc. sub. cit. II, 1858, 452.
Pisum obscurum, ADAIS, loc. sub. cit. II, 1858, 660.
Pisum kurtzi, ADAMS, loc. sub. cit. II, 1858, 660.
Pisum rubellum, ADAMS, loc. sub. cit. II, 1858, 660.
Pisumn zonatum, ADAMS, loc. sub. cit. II, 1858, 660.
Pisidium retusumn, PRInE, Proc. Zool. XXVIII, 1860, 322.
This species is distributed over such a vast area of country, and
varies so much according to the different localities in which it is
found, that it is hardly surprising  that its numerous varieties




PISIDIUM. 
should have been mistaken for so many species.  P. caseqrtanum.,
its foreign analogue, to which it bears the closest resemblance.
and from which it is very difficult to separate it, is likewise widely
distributed and subject to much variation.
P. abditum is our most common species, and occurs generally
in great numbers; its epidermis, though usually light yellow, is
at times, according to the habitat of the shell, of a much darker
color; the surface is at times also quite rough and the stripe coarse.
Compared with P. nov-eboracense, to which it is nearly allied,
it differs in being less heavy, more rounded,. less full, the beaks are
less large, the hinge-margin is straighter, the anterior extremity,
which in the P. nov-eboracense forms a declivity from the beaks, is
more regularly rounded, the distance from the beaks to the basal
margin is less great, the exterior surface is much smoother, and
the epidermis of a lighter color.
Fig. 73.
P. abditurm.
S. Pisidium   simile, PRIME. — Shell rounded-oval, very much
elongated, very inequilateral, slightly compressed; anterior
side rounded, posterior subabrupt; beaks moderately full,    Fig. 74.
raised; surface smooth, epidermis light straw color; hingemargin nearly straight.
Long. 0.14; Lat. 0.13; Diam. 0.07 inches.
Hab. At Guadeloupe, in the West Indies.  (Cabinets of    P. simile.
Smithsonian Institution, Morelet, and Prime.)
This species bears the greatest resemblance to P. abditum in
outline and size; it is, however, a little more elongated, and more
compressed.
9. Pisldium  chilense, DESHAYEs.-Shell small, delicate, moderately inflated, elongated, inequilateral; anterior side a little
longer, angular at end, posterior subtruncate; beaks large,   Fig. 75.
full, somewhat raised; stripe very fine, surface smooth; epidermis light yellow; hinge-margin nearly straight; cardinal
teeth small, but distinct; lateral teeth a little elongated.
Hab. South America, at Valparaiso, and at Coquimbo in
Chili. (Cabinets of Smithsonian Institution, Cuming, and Prime.)




7 0                  AMERICAN CORBICULADA.o
Cyclas chilensis, D'ORBIGNY, Voy. en Am6r. 1846, 568, pl. 83, f. 11-13.
Pisidiuzm chilense, DESHAYES, Biv. Brit. Mis. 1854, 284.
Pera chilensis, GRAY, Brit. Mus. Shells of S. Amer. 1854, 69.
Pisum chilense, DESRAYES, Biv. Brit. Mus. 1854, 284.
Musculium chilense, ADAMS, Rec. Gen. II, 1858, 451.
Corbicula chilensis, PRIME, Proc. Acad. Nat. Sci. Phila. 1860, 269.
Pisidium angulatum, PRIME, Proc. ZoO1. XXVIII, 1860, 322.
I have not seen any original specimens of this species; but
from the description and figure given of it by M. D'Orbigny, I
have no doubt that it is the same shell I described as new fiom
the collection of Mr. Cuming, under the name of P. angulatumn.
Compared with P. abditum, to which it bears a general resemblance, it is smaller, a little more full, less elongated, and less
rounded laterally.
10. Pisidium   jaxnaicense, PRIME.-Shell small, oval, short,
subequilateral, somewhat compressed; anterior side very
Fig. 76.  little longer, somewhat narrower, tapering to a well-rounded
extremity; posterior subtruncate; beaks small, not prominent; striae not perceptible, surface smooth, epidermis light
straw color; cardinal teeth small, lateral teeth moderately
P. jamaicense.
Long. 0.083; Lat. 0.075; Diam. 0.05 inches.
Hab. Jamaica, in the West Indies.  (Cabinet of Prime.)
Cyclas pygmea, C. B. ADAMS, Contrib. Conch. 1849, 44.
Pisuni adacmsi,' DESHAYES, Biv. Brit. Mus. 1854, 284.
Musculium pygmeum, ADAMS, Rec. Gen. II, 1858, 452.
Pistum pygmeun, ADAMs, loc. sub. cit. II, 1858, 660.
A rare species.  The only specimens I have seen are those in
my cabinet, which I received some years since from the late Professor Adams. Remarkable for its short, compact appearance.
11. Pisidium  pulchellumn, DESHAYEs.2-P. testa ovata, inflata,
tenui, subloevigata, epidermide viridescente, invequilaterali; latere antico
elongato, rotundato; latere postico brevi, obtuso; intus albicante.
Hlab. South America, at Maldonardo in Uruguay.
Not to be confounded with Pisidiazm  adamnsi, PRIME (Cyclas nitida.,
MIGHELS), from Maine.
2 Not to be confounded with Cyclas pulchella, HANLEY, or Pisidium pZ,[chellum, JEN.YNS, a variety of P. casertanum, PohjI.




PISIDIUIM.1
Cyclas pulchella,' D'ORIGcNY, Guer. Mag. Zool. 1835.
Pisidium pulchellum, DESHAYES, Biv. Brit. Mus. 1854, 283.
Pisunz pulchellum, DESHAYES, Biv. Brit. Mus. 1854, 283.
fliusculium pulchellum, ADAMS, Rec. Gen. II, 1858, 452.
Sphwrium pulchellum, PRIME, Proc. Acad. Nat. Sci. Phila. 1860, 297.
It has not been my good fortune to meet with this species,
which A.l D'Orbigny likens to P. fontinale, of France; he found
it in considerable abundance.
12. Pisidiumn  ferrugineum,2 PRIME.-Shell small, roundedoval, globose, slightly inequilateral; anterior side somewhat produced; margins rounded; beaks tubercular at       Fig. 77.
apex, very distant; surface smooth; epidermis light
yellow; hinge-margin rounded; cardinal teeth large,
separate, anterior tooth more prominent; lateral teeth
distinct.
Long. 0.17; Lat. 0.13; Diam. 0.11 inches.
HTab. North America, in the States of Maine and New   P. ferruzgineum.
York.  (Cabinets of the Boston Society, Smithsonian
Institution, Lewis, Jay, and Prime.)
Pisidium ferrugineum, PRIME, Bost. Proc. IV, 1851, 162.
Remarkable for the elevation of its beaks, which stand forth on
the upper portion of the shell in the shape of large tubercles,
which are generally coated with some dark ferruginous substance.
It differs from P. abditum in being smaller, more inflated, not so
elongated, and more equilateral.
One of our most common species, found usually in company
with P. variabile and P. ventricosum.
Fig. 78.
p. ferrugineum.
I Not to be confounded with Cyclas pulchella, HANLEY, or Pisidium pulchellum, JENYNS, a variety of P. casertacturn, POLI.
2 Not to be confounded with Pisum ferrugineum, DESHAYES, Biv. Brit.
Mus. 1854, 281, which is Sphiriunm ferrugineum, KRAUss, of Africa.




'12                  AMERICAN CORBICULADAE.
13. Pisidium   ventricosnum     PRAnE.- Shell small, roundedoval, globose, ventricose, somewhat oblique, slightly inequilateral, anterior side produced, posterior subtruncate;  Fig. 79.
beaks small, protuberant, distant, situated towards the
posterior side; surface smooth, yellow; hinge-margin
curved; cardinal teeth separate; lateral teeth short.
Long. 0.11; Lat. 0.095; Diamn. 0.085 inches.
HEab. North America, in the State of Massachusetts.
P. ventricosum.
Cabinets of the Boston Society, Smithsonian Institution,
Lewis, Jay, Prime, and others.)
Pisidiurn ventricosum, PRIME, Bost. Proc. IV, 1C51, 68.
Musculium veutricosum, ADAMs, Rec. Gen. II, 1858, 452.
Pisum ventricosum, ADA31S, loc. sub. cit. II, 1858, 660.
This small, globose species is not likely to be confounded with
any other but P. rotundatum, than which, however, it is more
oblique, the margins are more abrupt, and the beaks more terminal
and very much smaller.  It is very nearly allied to P. obtusale,
of Europe.
Fig. 80.
P.:entricosum.
4. Pisidiunr   rotuldatuim, PRIME. -- Shell small, roundedoval, globose, ventricose, inflated, subequilateral; anterior
and basal margins rounded, posterior margin  somewhat   Fig. 81.
abrupt; anterior side a little longer: beaks nearly central,
very large, prominent, rounded; surface glossy, yellow,
somewhat darker in the region of the beaks; hinge-margin
curved; teeth small.
P. rotundatum.
Long. 0.09; Lat. 0.07; Diam. 0.08 inches.
Hab. North America, in the region of Lake Superior. (Cabinets of
Agassiz and Prime.)
Pisidiuzm rotiundaturm, PRIME, Bost. Proc. IV, 1851, 164.
Musculium rotundatum, ADAMrs, Rec. Gen. II, 1858, 452.
Pisum rotundatum, ADAMS, 1Oc. sub. cit. II, 1858, 660.




PISIDIUa.                           7 3
This species, allied only to P. vent7ricosuM,   is remarkable for
the fulness of the beaks, which are not raised in proportion.
Fig. 82.
P. rotundatum.
15. Pisidium   occidentale,  NEwcoMB. —P. testa rotundatoovata, obliqua, inequilatera, hyalina vel fusco-cornea; natibus approximatis vic prominentibus; strive minutissimne.
Long. 4; Lat. 3: mill.
Hab. North America, at San Francisco (Ocean House), California. (Cabinet of Newcomb.)
Pisidium occidentale, NEWCOMB, Proc. Calif. Acad. Nat. Sci. II, 1863, 94.
I have not seen this species, which Dr. Newcomb says is allied
to P. variabile.
FOSSIL SPECIES.
16. Pisidiutm  contortnmi, PRIME.-Shell elongated, subrhomboidal, inequilateral, somewhat compressed; anterior side
produced, angular at end; posterior side short, subabrupt;   Fig. 83.
hinge and basal margins nearly straight; beaks terminal,
raised above the outline of the valves; strise light; hinge
comparatively strong; cardinal teeth distinct; lateral teeth
P. contortumo
elongated,
Long. 0.13; Lat. 0.07; Diam. 0.05 inches.
Hab. North America, at Pittsfield, Massachusetts. Post Pleiocene formation.  (Cabinets of Smithsonian Institution, and Prime.)
Pisidium contortum, PRIME, Ann. N. Y. Lye. VI, 1853, 65, pl. i, f. 2.
This species, which occurs rarely, was discovered, by Dr. Shurtleff, in company with P. ventricosurn.








APPENDIX.'v/. Corbicula perplexa, PRIME.-Testa transversa, ovato-subtrigona, inaequilaterali, compressa; latere antico breviore, rotundato; transversim dense et irregulariter striata-;:epidermide squalide
virescente vestita.                                         Fig. 84.
Shell transverse, oval, subtrigonal, inequilateral, compressed; anterior side shorter, rounded; posterior side somewhat narrower at extremity; valves moderately solid, interior
purplish-white with purple markings under the posterior
lateral tooth and with distant and more or less distinct purple   CorbicuZa
lines radiating from the apex of the shell towards the basal   perrplexa.
margin; stripe very close, irregular and indistinct; epidermis
of a soiled green; beaks small, somewhat raised; hinge-margin broad
with three unequal diverging cardinal teeth, the principal ones bifurcated;
anterior cardinal tooth in the right valve nearly obsolete; palleal impression terminating in a small and short sinus.
Long..48; Lat..40 inch.
"   12;  "  10 mill.
dab. South America.  (Cabinet of Prime.)
This species is very closely allied to Corb. limosa; it is however much smaller, more transverse, more produced on the
posterior side; the hinge is less solid, and the cavity of the valves
is deeper. I have failed to discover in any specimens of Corb.
perplexa the radiating colored lines, which are frequently met
with on the epidermis of Corb. limosa.
15'. Pisidium   ultramontanum, PiRIME. -Testa ovato-suborbiculari, subinsequilaterali, compressa, solidiuscula;
umbonibus parvis, subdepressis, parum prominulis.         Fig. 85.
Shell comparatively solid, oval-suborbicular, subinequilateral, compressed; anterior side much produced between
the extremity of the lateral tooth and the junction with
the basal margin; posterior margin rounded; beaks small,
not full, not much raised above the outline of the shell;
valves shallow in the cavity; hinge strong; strine delicate;  Pisidium
epidermis light brownish horn color.                    ultramontanum.
(7.5 )




76                          APPENDIX.
Long..20; Lat..16 inch.
"    5; "    4 mill.
Hab. North America, Canoe Creek in California.  (Cabinets of the
Smithsonian Institution and Prime.)
Remarkable for its spherical and flattened appearance; it is
unlike any other species indigenous or foreign.
157." Pisidium  consanguineum, PRIuME.-Testa minuta, trans,
versa, rotundato-ovata, inoequilaterali, compressiuscula; marFig. 86.  ginibus rotundatis; tenuissime striata; umbonibus tumidiusculis.
Shell small, transverse, rounded-oval, inequilateral, not
much inflated; margins rounded; beaks somewhat apiculated;
Pisidium   striae very delicate; epidermis light horn color; teeth robust.
consanguineum.             Long..16; Lat..12; Diam..12 inch.
"    4;  "   3;  "       3 mill.
Hab. Retiro, Monte Verde and Catalina da Guarra, Cuba, West Indies
(fide Wright).  (Cabinet of Smithsonian Institution, Wright, Wheatley,
and Prime.)
Very closely allied to Pisid. abditum, from  which it is very
difficult to distinguish it.




INDEX.
Amesoda, 32                            Cyclas acuminata, Prime, 37
albula, Prime, 37
Batissa, 1, 9, 10, 12                          altilis, Anthony, 65
argentina, D'Orb. 52
Cardium, 32, 59, 60                           aurea, Prime, 35
Conques, 1                                   bahiensis, Spix, 53
Coaquesfiuviatiles, 1                        bulbosa, Anthony, 38, 39
Corbicula, iv, 1, 2, 3, 10, 11, 12             calyculata, C. B. Adams, 51
Corbicula antiqua, iv, 9                       calyculata, 51, 52
brasiliana, Desh. 7                 cardissa, Prime, 49
chilensis, Prime, 70                caroliniana, Bose, 12
convexa, Desh. 3, 4                 caroliniensis, Bose, 12
cordata, lliorris, 9                castanea, Prime, 40
cuneata, Desh. 6                    chilensis, D'Orb. 70
cuneiformis, iv                     cferulea, Priine, 46
cytheriformis, M. c H. 9            coistricta, Anthony, 48
forbesii, iv                        cornea, Lam. 37, 39, 46
incrassata, Desh. 6, 7              crocea, Lewis, 49, 50
limosa, Desh. 5, 14, 75             dentata, Hald. 40
moreauensis, Ml. 6- H. 7, 8         detruncata, Prime, 48
nebrascensis, AlI. t H. 8           distorta, Prime, 36
obsoleta, Desh. 4                   dubia, Say, 62, 66, 67
occidentalis, M. ~ H. 8             eburnea, Anthony, 46
paranensis, Desh. 3, 4              edentula, Say, 37, 38
perplexa, Prime, 75                 elegans, C. B. Adams, 39
rotunda, Prime, 4, 5                elevata, Ilald. 45
semisulcata, Desh. 5, 6             emarginata, Prime, 43
truncata, Prime, 7                  fabalis, Prime, 40
ventricosa, Prime, 3                flava, Prime, 43
woodiana, 2                         fontaineii, D'Orb. 21
Corbiculade, 1                                formosa, MIeek & Hayden, 5M
Cordula, 59                                  firagilis, Meek & Hayden, 5H
Cornea, 32                                    fUscata, Rafin. 38
Corneocyclas, 32                              gigantea, Prime, 34
Cyanocyclas, 11                               gracilis, Prime, 48
Cycladacea, 1                                 inornata, Prime, 37
Cyclad dr, 1                                  jayensis, Prime, 47
Cycladea, I                                   lasnamnpsis, Rafin. 34
Cycladles, 1                                  lenticula, Gould, 52
Cyclades, 1                                   limosa, D'Orb. 5
Cycladia, 1                                    littoralis, Fer. 54
CJycladine, 1                                 maculata, Anton, 53
Cycladites, 1                                  cmaculata, Morelet, 55
Cyclas, 2, 9, 11, 32, 59                       maritima, D'Orb. 29
( 7 )




7 8                              INDEX.
Cyclas minor, C. B. Adams, 68         Cyrena cubensis, Prime, 29, 30
mirabilis, Prime, 46                  cumingii, Desh. 24, 25
modesta, Prime, 37                     cuneata, Jonas, 6
modioliformis, Anton, 54               cuneiformis, Per. 7
moquiniana, Gass. 54                  dakotensisM. S H. 31
nitida, Migh. 63, 66, 70              densata, Conrad, 31
nobilis, Gould, 41                    floridana, Conr. 23, 28, 29, 30
o rbicularia, Barratt, 46.            fontaineii, Carp. 18, 21
ovalis, Prime, 41                      fortis, Prime, 17
pallida, Charp. 45                    fragilis, Desh. 22, 23
paranensis, D'Orb. 4                   globulus, Jonas, 6
partumeia, Say, 46                     iflata, Desh. 24, 25
patella, Gould, 42                     inflata, Phil. 26
pellucida, Prime, 51                   insignis, Desh. 15, 16
ponderosa, Prime, 34                   intermedia, Meek & Hayden, 8
pulchella, D'Orb. 71                   intermedia, Melville, 8
pulchella, Hanley, 70, 71              isocardioides, Desh. 25
pygmea, C. B. Adams, 70                limosa, Gray, 5
rhomboidea, Say, 34, 39               maritima, C. B. Adams, 24,
rosacea, Prime, 50                       25, 27, 28, 29
saratogea, Lam. 34, 35                 meridionalis, Prime, 19
securis, Prime, 49                     mexicana, Sowerby, 3, 12, 15,
spharica, Anthony, 50                    22, 23
similis, Say, 34, 35                   moreauensis, M. & H. 8
simplex, Prime, 37                     nitidula, Desh. 20
solida, DeKay, 34                      notabilis, Desh. 28
solidula, Prime, 36                    obscura, Prime, 15, 28
staminea, Conrad, 38                   occidentalis, M. 8c H. 8
striatella, Fer. 54                    olivacea, Caqp. 15, 17, 18, 21
striatina, Lam. 34, 37                 ordinaria, Prime, 19, 20
subelliptica, M. & H. 59               panamensis, Prime, 24
sulcata, Lam. 34, 35                  paranacensis, D'Orb. 4
sulculosa, Charp. 40                  peruviana, Desh. 30, 31
tenuis, Prime, 47                      placens, Hanley, 20, 21
tenuistriata, Prime, 37, 38            pullastra,-M'rch, 26
transversa, Say, 48                    radiata, Hanley, 13, 14, 15,
trianzgularis, Say, 36, 37               16, 17, 20, 21, 24
truncata, Linsl. 51                    recluzii, Prime, 24
variegata, D'Orb. 5                    regalis, Prime, 18, 19, 20
veatleyii, C. B. Adams, 56             salmacida, iliorelet, 29, 30
venezuelensis, Prime, 54               solida, Phil. 14, 19, 20
Cyclasidw, 1                                  sordida, Hanley, 13
Cyprina, 9                                    subquadrata, Desh. 24
Cyprina arenaria, Meek & Hayden, 31           triangula, v. d. Busch, 14, 15,
Cyrena, iv, 1, 2, 3, 9, 10, 11, 12, 26, 30      23
Cyrena acuta, Prime, 21, 22                   truncata, Lam. 7
equtilateralis, Desh. 22, 23          tumida, Prime, 26
altilis, Gould, 15, 23                varians, Carp. 15, 22
angulata, Desh. 26                    variegata, D'Orb. 5, 6
anomrala, Desh. 28, 30                violacea, Lam. 10
antiqua, Fer. 6               Cyrenide, 1
aretata, Desh. 13, 16
boliviana, Phil. 27           Euglesia, 59
californica, Prime, 23
cali/brniensis, Prime, 24     Gallileja, 59
caroliniensis, Lam. 12, 13    Geloina, 11
colorata, Prime, 29, 30
cordibormis, Recluz, 25       Isocardiam cor, 27




INDEX.                                 79
Lucinla, 60                           Pisidium consanguineum, Prime, 75
Lucina lenticula, Gould, 52                      contortum, Prime, 73
diaphaumn, Hald. 54
2Mactra, 11                                      dubium, Hald. 62
]liusculium, 32, 59, 61                          ferrugineum, Prime, 71
iMfusculium  abditum, Adams, 68                  granide, Whitt. 66
abruptum, Adams, 62                 jamaicense,: Prime, 63, 70
altile, Adams, 65                   kurtzi, Prime, 68
bahiense, Adams, 53                  minus, Stimp. 68
chilense, Adams, 70                  moquinianum, Bourg. 54
cicer, Adams, 65                     notatzun, Prime, 68
compressum, Adams, 65                nov-eboracense, Prime, 67,
dubium, Adams, 62                      69
kurtzi, Adams, 68                    obsczrueri, Prime, 68
maculatum, Adams, 53                 obtusalej 72
minus, Adams, 68                     occidentale, Newc. 73
modioliforme, Adams, 54             plenumz, Lewis, 68
nov-eboracense, Adams, 67            pulchellum, Jenyns, 70, 71
obscurum, Adams, 68                  regulare, Prime, 68
pulchellum, Adams, 71                resartum, Ingalls, 68
pygmeum, Adams, 70                   retuzsum, Prime, 68
rotundatum, Adams, 72               rotundatum, Prime, 72
rubellum, Adams, 68                rubellum, Prime, 68
variabile, Adams, 66                 rubrum, Lewis, 68
veatleyi, Adams, 56                  simile, Prime, 69
ventricosum, Adams, 72              tenellum, Gould, 68
virginicum, Adams, 62                ultramontanum, Prime, 75
zonatum, Adams, 68                   variabile, Prime, 61, 63, 64,
lIusculus, 32, 59                                  65, 66, 67, 71, 73
veatleyii, Petit, 56
Nux, 32                                          ventricosum, Prime, 61, 71,
72, 73
Pectunculus, 32, 59                             virginicum, Bourg. 61, 62,
Pera, 59                                           63, 65, 66
Pera chilensis, Gray, 70                        zonatum, Prime, 68
Physemoda, 59                          Pisum, 32, 59, 61
Physemoda equalis, Rafin. 62          Pisum abditum, Desh. 68, 76
Pisidium, v, 2, 32, 33, 35, 47, 53, 59,      abrutpttum, Desh. 62
60, 61, 64                                 adamsi, Desh. 63, 70
Pisidium abditum, Hald. 63, 65, 67~           altile, Desh. 65
68, 69, 71, 76                   bahiense, Desh. 53
abruptum, Hald. 62                  chilense, Desh. 70
adamsi, Prime, 62, 63, 70           cicer, Adams, 65
weqtale, Rafin. 62                  compressum, Desh. 65
mquilaterale, Prime, 63, 64,       dubium, Desh. 62
65                              ferrugineum, Desh. 71
altile, Anthony, 65                kurtzi, Adams, 68
amnicum, 62                         maculatum, Desh. 53
amplurm, Ingalls, 67               minus, Desh. 68
angulatum, Prime, 70               modioliforme, Desh. 54
arcunatum, Prime, 65               nov-eboracense, Adams, 67
casertanum, Bourg. 69, 70,         obscurum, Adams, 68
71                               pulchellum, Desh. 71
chilense, Desh. 69, 70             pygmeum, Adams, 70
cicer, Prime, 65                   rotundatum, Adams, 72
compressum, Prime, 64, 65,         rubellum, Adams, 68
66                               variabile, Adams, 66
conicum, Baudon, 65                veatleyii, Desh. 56




8 0                              INDEX.
Pisum ventricosum, Adams, 72         Sphserium  pulchellum, D' Orb. 71
viryinicum, Desh. 62                      recticardinale, M. ~: H. 58
zonatum, Adams, 68                        rhomboideum, Say, iv, 34,
Polymesoda, 11                                    39
rosaceum, Prime, 50, 51
Sphaerium, iv, 2, 4, 32, 33, 35, 37, 39,        sec-uris, Prime, 49, 50
53, 56, 59, 60, 64                 solidulum, Prime, 36, 37,
Sphaerium africanum, iv                            38
argentinum, D' Orb. 52               solidum, iv
aureum, Prime, 35                    sphaericum, Ant7ionyx50
bahiense, Spix, iv, v, 53,           spokani, Baird, 44
54                                 stamineum, Conr. 38, 42
barbadense, Prime, 53, 54            striatinum,Lam. 37, 38, 4'
contractum, Prime, 48, 49            subellipticum, M. 6-.r
corneum, iv                          subtransversum,Prime,5.
cubense, Prime, 58                   sulcatum, Lam. iv, 33, 34
dentatum, IHald. 40                    42, 57
dubium, Desh. 62                     tenue, Pr ime, 47
elevatum, Hald. 44, 45               triangulare, Say, 36
emarginatum, Prime, 43               transversum, Say, 47, 48,
fabalis, Prime, 40                     49
ferrugineum, Krauss, 71              truncatum, Linsley, 46,
flavum, Prime, 42, 43                   51, 52
formosum, M.,c H. 59                tumidum, Baird, 43, 44
jayanum, Prime, 46                   veatleyii, C. B. Adams,
lacustre, Fer. iv, 51, 52               56, 57
lenticula, Gould, 51, 52             vermontanum, Prime, 42,
maculatum, 2forelet, 53,                43
55                                 viridante, iforelet, 57, 58,
~meridionale, Prime, 53,
55, 57                  Tellina, 2, 32, 59, 60
imodioliforme, Anton, 54,  Tellina fiuminalis, 2
55                             fluminea, 2
nitidum, Desh. 63                fiuviatilis, 2
nobile, Gould, 41                 limosa, Maton, 5
occidentale, Prime, 41            pusilla, Dillw. 62
ovale, Stimpson, 41               virginica, Gml. 62
partumeium, Say, iv, 41,
45, 46, 51              Velorita, 1, 10, 11, 12
parvulum, Prime,          Velorita cyprinoides, 11
patella Gould, 40, 42, 43   Veneriadw, 1
planum, Ml. g' H. 58      Venulites, 2
portoricense, Prime, 56    Venus, 2, 9, 10, 11