LIBRA RY

‘New York State Veterinary College

ITHACA, NEW YORK

eiL Simpson, George B.
4 ie 31

Anatomy and Ph:siology of Polygyra
albolabris and linax maximus

 
 

 

a University Library
QL 431.861

y and physiology of Polyg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

           

DATE DUE

GAYLORD

PRINTEDINU.S A.

 

 
University of the State of New York

ye

 

BULLETIN

OF THE

New York State Museum

‘FREDERICK J. H. MERRILL Director

No. 40 Vol. 8

October Igor -

ANATOMY AND PHYSIOLOGY

OF

POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS

! AND

EMBRYOLOGY OF LIMAX MAXIMUS

BY

Q L GEORGE B. SIMPSON

Division of paleontology
Tal
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ALBANY
UNIVERSITY OF THE STATE OF NEW YORK

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Mé6qm-Jeo-3000 Price 25 cents
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{S ag a

~ LIBRARY. |

4 OF Ss

University of the State of New York

 

BULLETIN

OF THE

New York State Museum

FREDERICK J. H. MERRILL Director

No. 40 Vol. 8

October 1901 oe “

 

ANATOMY AND PHYSIOLOGY

OF
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS

AND

EMBRYOLOGY OF LIMAX MAXIMUS

BY
GEORGE B. SIMPSON

Division of paleontology

ALBANY
UNIVERSITY OF THE STATE OF NEW YORK
Igor
QL
£3/
Shy

(VY: Ok

CON TEN FS

IBrefacevisccizcctcccsc a secact Wile SioteGss 2 dy jedewisieicinve ce uaceee esas, sce pe erena Sareea atoteretere 239
Introductionsncceecitssscuasiowansce cmon bee eceees cedeorsaecs eens ebed Secu 241
Methods and apparatus cosccn see wscemscticccue cuticles iene seme ceeiese 241
Methods-of killing and:manipulating «..2..c5..-ccceeeeceereceeeceoe eels ious 241
Habits:.-2s.ceccecsd enue tobe Sete wets Jue SSise emma teeidek semen ceceseelesee 241
Poly gy ta al bolab nis: cues ise osss-qesscoes sens ccscssteeseckecalesewiees 244
Slrelecds coca een hen ceiis-s Sele laitiaie oaen celss roles eusme@ nec ee auais aise els temtyne 244
External fedtureswcciccvcucevecicse cra vice wee ees cee Seer cede Sees aeeee 245
Movementiccwsncedecucacecsciccudbid nun Sacer emirates benenieeeaS 247
Podd—carnivorous: habltss sec ssn wie cisiee ce ees emete neat euind cece cases ese, 247
Digestive System oc suteie isles eee wing wintesieiiwe Welgia Selena asides eerie 249
Pedal 2oland sais eues-casc a cass Sectnbcictecie dieisisce witness tate ea! aSaieS meu emcee ce 254
Generativesystempitesccsasaes Saeleny svete ais S ove Bee siewees eeucdoedemeeeenn 255
Description of a species of Entozoa .... 2... .2-. 2225 2-2-2 ee eee oe eiereereu 261
Circulatory Systems sies witches Semin scare wee nels Shee ee cece cept eeeeceN 262
INERVOUS SYSTEM occ eccerceexpeici scare deisepsiabin wim ele beaters ele ie eels 268
Special organs Of ‘Senseec cee ajeiec seieeecide ssiceid wists sicinieleceie: ciciein’asae'ennieecels 272
imax maxims: Ty. cicacevncceusetie ound ewekloueheetiiccve sack Geese a 277
DIGEStIVe SYSTEMS x. aicensccincesiccw 2 <isa.dicieeinicsaiGinia die einsey iowa Sears einen emia DUO
Generative: systemice 5.2 .cadubae reap ie sbee Seki nee ects eee eae sees cases 279
Circulatory SySteits,c255,2acccienaoeescectesosseetaseh eactapeceeee cane dees 280

Nervous: syste miuissean acearetectisiecceated <eebweed tees Sete acne sas weds 5 283
MGS CHIE SY Ste Miccas facto tics mciaas Oi a apeietecrcthciesciolbe even amare cate ce erence 28
Embryology (scson eet c ids Se dtonuuvissenmcnei eee cei oes ace eteeele ness “200
imerotlayin ge CG Asie. e808 Screncracrnaeisigece emeaeee wmemem eatin eesteeris 293
Rateiol orowthrcerstdaod wcemenieeun ecctvens edna eRenewesereeseoeacsacce 294

Explanation of plates

Polygyra “albolabris, plates: I-14 woes see wnt o icicie cide nicle's ccclale aise bin se eauegnn BOR
Limax maximus, plates 15-28 . 2... .200 cece cone coun cee cane eee eee ee eens 302

Pid ei tee ieie cis eles ti cfateiete hie weis eeieeme ues ete iienea ese cbtece essence one 313
PREFACE

This work has been written for the use of individual students,
as well as for classes in schools and colleges. No similar work
on the snail has been published in this country, and in my own
investigations I have seriously felt the need of one.

I have endeavored to write a work which will enable the stu-
dent, without a previous knowledge of the subject, satisfactorily
to pursue his investigations. I have, therefore, commenced at the
beginning, giving explanations in regard to the instruments
necessary, methods of dissection, how to collect the animals, etc.,
followed by a plain, but full, description of all the organs, with-
out the use of too many technical terms, and unencumbered by
theories.

I have made very full illustrations of all the organs and parts
of organs, enabling the student at once to see their form and po-
sition. These illustrations are accurate copies from nature and
in no case are they diagrammatic.

The manuscript of that portion of this work treating of anat-
omy and physiology was kindly reviewed by Prof. H. A. Pilsbry,
of Philadelphia, and to him I am indebted for suggestions, spe-
cially in regard to nomenclature. I am also indebted to Prof.
E. G. Conklin, of the University of Pennsylvania, who reviewed
that portion treating of the embryology of Limax.

GrorGp B. Simpson
 

 

 

Dissecting microscope and instruments
New York State Museum

 

POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS

INTRODUCTION
Methods and apparatus

Specimens of Polyg yra and Limax may be easily kept
in captivity by placing them in @ box in which there are about 4
inches of earth covered with dead leaves. The earth must be
kept moist. The box must be covered with mosquito netting or
tarlatan. The mosquito netting will be sufficient for adult indi-
viduals, but the young of Limax would escape easily through
its meshes.

For the study of the histology and embryology a compound
microscope is necessary, with 2 inch, 2 inch and } inch objec-
tives. A dissecting microscope is almost indispensable. I have
used, for that purpose, one manufactured by Bausch & Lomb of
Rochester (N. Y.), known as the “laboratory dissecting micro-
scope,” fitted with a Hastings aplanatic lens. A cut of this in-
strument is given herewith. Two pairs of fine scissors will be
necessary, one pair with straight points, the other with curved
points; one or more fine scalpels, and two pairs of fine forceps,
one straight and the other curved. A pair of stronger forceps and
a pair of fine pliers will be needed to remove the shell of
Polygyra. Dissecting needles are also necessary. These
can be made by forcing the heads of fine needles, by means of
a pair of pliers, into the end of a round stick of small diameter.
The point of one of these needles should be bent so as to form
a hook, first heating the end of the needle to a white heat.

Methods of killing and manipulating

I have tried all of the various methods recommended for
kiling Polygyra and Limax, and find only one that is
uniformly successful, and that is drowning. In using hot water
and various chemicals, in nearly every case the animal is
more or less contracted, and thus rendered useless for the pur-
242 NEW YORK STATE MUSEUM

pose of a successful dissection. In drowning the animal, I have
used a fruit-preserving jar, as being more convenient than a wide-
mouthed bottle. The jar should be completely filled with water,
so that, when the cover is fastened on, there will be no air space
left. The animals being placed in the water and the cover
screwed on, the jar should be left undisturbed for 48 hours; it
requiring about that length of time to drown the animals. Re-
maining undisturbed, they will die fully extended; but, if the jar
is disturbed in the meantime, more or less contraction will take
place. The animal when dead should be thoroughly washed to
free it from all adhering mucus, and placed in alcohol diluted
with about two thirds the amount of water, additional alcohol
being added from day to day till the mixture consists of about 75%
of alcohol. The animals should then be removed and placed in
undiluted alcohol, when they will keep indefinitely. If placed at
once in strong alcohol, the action of the fluid on the integument
prevents the proper preservation of the internal organs.

To remove the shell, preparatory to dissecting the animal,
break the peristome with a small pair of pliers. The remainder
of the shell can be removed with a pair of forceps, carefully break-
ing off a small piece of shell at a time till it is removed to the
apex. The columella can be removed by holding the lower part
between the thumb and forefinger of the left hand, and turning
the animal with the right. As the columella is like a screw, the
animal readily becomes detached by this movement.

In dissecting the animal, a circular china dish about 4 inches
in diameter and 2 in depth will be necessary; also a piece of sheet
cork as large as will lie at the bottom of the dish, fastened to a
thin sheet of lead with either string or rubber bands. It is best
to have the lead of the same size as the cork. This leaded cork
is to be placed in the bottom of the dish, and the dish filled with
alcohol. If the animal has once been placed in alcohol, all dissec-
tions should be made in alcohol, but freshly killed specimens may
be dissected in water, and many of the organs at this time present
a much more natural appearance than when acted on by alcohol.
Place the animal on the cork and fasten it down with small pins,
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 243

or, better yet, with very fine, short needles, inserted through the
margin of the foot. Then, with the fine pair of scissors, com-
mencing at the head, cut through the integument along the center
of the back, taking care not to injure any of the organs below.
The integument is now to be removed from the dorsal part,
turned back and fastened to the cork, removing the needles from
the margin of the foot and putting them through the edges of the
integument. All the organs of the anterior part of the snail are
thus brought into view, and farther dissection of the organs can
be intelligently made.

In the case of the Limax nearly all the organs will be
brought into view by turning back the integument; but great
care must be taken in this genus in cutting through the integu-
ment not to injure the pulmonary chamber, as it is situated very
near the surface. Also every precaution should be taken that
the points of the scissors shall not go below the integument, or
the intestine and upper surface of the stomach will be mutilated,
and a successful dissection rendered impossible.

Habits

Polygyra albolabris. The snails of this species are found in
woods near fields, in ravines and in other situations. They re-
main concealed through the day when the sun is shining, coming
forth for their food toward evening and after showers. It is at
these times that they are most easily found during summer. Fre-
quently they may be found on the under side of boards, logs and
stones. During cold weather they hibernate, partially burying
themselves in the ground, with the apex of the shell downward.
At this time they are very easily found by scraping away the
dead leaves so as to expose the surface of the ground. While
hibernating the animal is completely withdrawn in the shell, the
mouth of which is closed by a mucous excretion, which becomes
hardened on exposure to the air. It is stated by nearly all
writers on this subject that there is always a perforation in this
membrane to allow the passage of air; but I have observed
numerous cases where the membrane was entire.
244 NEW YORK STATE MUSEUM

Limax maximus is found in gardens, where it is very destructive
to vegetation. During the day it secretes itself; but it may easily
be found, by the aid of a lantern, while feeding at night.

POLYGYRA ALBOLABRIS Say, sp.
Shell

The shell of Polygyra is turbinate, spiral; consisting in
P. albolabris of five volutions, coiled around a hollow axis
known as the columella. The columella is open at the base in
immature specimens, but in adults it is closed by a growth of the
shell. When the shell emerges from the egg, it consists of one
volution only. Farther growth of the shell takes place in the
manner hereafter described.

The shell consists of three parts or layers: the outer com-
monly, but wrongly, termed the epidermis—cuticle or Carpen-
ter’s name, periostracum, is preferable; next a prismatic part;
finally a laminate part. The prismatic and laminate layers are
of about equal thickness, and together form the greater part of
the entire thickness of the shell.

The cuticle is thin; in P. albolabris yellowish brown in
color. It is without sensation, like the human scarf skin. Its
office is to protect the shell from chemical action, which other-
wise would injure or destroy it. After the death of the animal
it fades and becomes brittle, or is entirely destroyed in situations
in which during life it would not be affected.

The shell is formed by the thickened margin of the integument
covering the visceral mass. According to Carpenter, “the shell,
as before stated, is formed by the mantle of the shellfish, indeed,
each layer of it was once a portion of the mantle, either in the
form of a simple membrane or as a layer of cells, and each layer
was successively calcified (or hardened by carbonate of lime) and
thrown off by the mantle to unite with those previously formed.”
According to Huxley, the shell growth is not a case of conversion
but of excretion, and the shell is built up by successive excretions
of membranous laminae, in which granules of carbonate of lime
are deposited.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 245

The prismatic part of the shell is apparently formed by the
deposition of calcareous matter in prismatic, generally hexagonal,
cells, which are themselves formed by the successive secretions of
fenestrated laminae, deposited by the margin of the mantle (pl.
2, fig. 12 and 15).

The laminar part is apparently composed of numerous thin
laminae varying in thickness. In many thin sections which I
have examined under the miscroscope I have seen no trace of the
prismatic structure in this part of the shell. The nacreous layer
is very thin, forming the inner stratum of the shell, and is of a
somewhat pearly appearance. This layer is a part of the
laminar stratum, though it seems to be discernible, and in the
broken edges of the shell is always distinct and is distinguished
by its lighter color.

Till the shell reaches maturity the margin is very thin; but
when mature the margin becomes greatly thickened and reflected,
forming a broad peristome (pl. 1, fig. 8, 4-7, 12). It is apparently
formed by the part of the mantle depositing the prismatic layers,
as nearly its entire thickness is of prismatic structure (pl. 2,
fig. 13, 14).

If the margin of the shell is broken, it can be repaired by the
animal; but, if any other part of the shell is broken, complete
renewal is impossible, as the prismatic and cuticular layers of the
shell are deposited only by the thickened border of the mantle.
A mucoid substance in such cases is excreted and becomes calci-
fied, taking the place of the missing shell; but any considerable
breakage of the shell, except at the margin, is liable to be fatal
to the animal. In collecting specimens, sometimes by accident
the shells were broken; in nearly every case the animals died
within a few days.

External features

The ventral part of the animal is expanded into a locomotor
organ or foot, which is a thick, vermiform body with a ribbon-like
ventral disk. The head is situated at the anterior extremity,
and is obtuse; from it protrude two pair of tentacles, the upper
246 NEW YORK STATE MUSEUM

and much the longer pair containing the eyes, the lower and
shorter pair, the olfactory nerves. The mouth is situated at the
anterior basal part of the head. Immediately below it is the
opening into the pedal gland. The anterior upper part of the
body is rounded; the posterior part is more acute.

The dorsal part of the animal is produced in a spirally coiled
mass, containing the whole of the digestive gland, and parts of
the alimentary, circulatory and reproductive organs, and is there-
fore known as the visceral mass.

The integument of the foot consists of a thick mucous-secret-
ing membrane, with a muscular substratum. There are numer-
ous mucous glands occupying nearly the whole of the membrane.
The muscular substratum consists of unstriped fibers, arranged
longitudinally, transversely and obliquely. Interior to this in-
vestment of the foot is a muscular membrane inclosing the di-
gestive and reproductive organs, which is sometimes called the
peritoneum.

The dorsal part of the animal is inclosed in the shell and is
an exact mold of the shell. The integument of this part is very
thin and semi-transparent and is known as the mantle. Where
the visceral sac joins the foot the mantle is very much thickened,
forming a muscular collar, which is the shell-building organ of
the animal.

When the animal is at rest or alarmed, the foot is contracted
entirely within the shell, occupying the space at other times
filled by the pulmonary cavity. The pulmonary chamber is very
large and is situated in the outer part of the lower whorl. When
the foot is protruded, the pulmonary rete still remains in contact
with the shell, thus leaving a large cavity. It is into the space
obtained by the collapse of this cavity, when emptied of air, that
the animal withdraws when contracted. Thus the pulmonary
chamber of testaceous snails is as much larger than the chamber
of the naked slugs, as the volume of the foot superadded.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 247

Movement

The snail moves with a slow, gliding motion, produced by the
muscles of the pedal disk. First the hinder part of the foot is
drawn up, and the part immediately anterior to it is extended.
This part is then contracted, and the part immediately anterior
to it extended. These movements take place the entire length
of the body, following each other so quickly that a gliding mo-
tion is produced. This contraction and expansion are confined to
the central part of the pedal disk, the margins of the foot having
a lateral undulating movement of their own.

The movement of the muscles of the middle part of the pedal
disk gives rise to a very peculiar appearance, as if there were a
channel through which oval drops of a transparent fluid were
rushing in quick succession. Each contraction and expansion of
the muscles of each part of the disk give the appearance of one
of these drops of fluid, and, as these movements take place in
rapid succession along the whole length of the foot, beginning
at the posterior and continuing to the anterior extremity, the
optical delusion of rushing drops of water is created.

If a snail is placed on a thin piece of glass, and the under part
is observed while the snail is in motion, this movement can be
‘observed, or if a Limax is held with the fingers in such a
position that the under part of the body is uppermost, when it
struggles to escape the appearance is the same, the action of the
muscles being the same as when the animal is in actual motion.

Food—carnivorous habits

The snails which I have kept in confinement for three years
have been fed on apples and lettuce, and occasionally cabbage.
At first I placed lettuce in the box, but they refused to eat it.
After several days I placed pieces of apple in the box, and these
they ate ravenously. I fed them on apples for a month or more,
when they seemed to tire of them and refused to eat. After a
little time I placed lettuce in the box; this they ate, and since
that time it has been their principal food.
248 NEW YORK STATE MUSEUM

The popular belief that snails will feed on almost any vegetable
is erroneous. I find that they are very particular regarding their
food. I have placed spinach, young beet leaves and several other
kinds of tender vegetables in the box, but they have refused to
eat them.

Binney speaks of the carnivorous habits of Circinaria
concava, and also speaks of Polygyra sayi devouring
its own species. John Walton, in Mollusca of Monroe county, says
of the cannibalistic habit, in some of the species: “I had abun-
dant evidence the past summer inthe Zonites fuliginosa;
fully one third of the specimens of this species, taken during a
special search by myself and pupils, were found devouring shells
and animals, sometimes their own species, but more frequently
the young of P. albolabris, thyroides, sayi, and Tri-
odopsis palliata. This was in July, and possibly the time
of the year had something to do with the habit, as in the case of
some seed-eating birds that are known to consume large quanti-
ties of insects in feeding their young and probably themselves
during the breeding season ”.

I would suggest, in regard to their carnivorous habits, that, if
the season was very dry, there may have been a scarcity of suit-
able vegetable food. I have raised over six hundred specimens
' from the egg, and I have found that, when the adult animals were
plentifully supplied with food, the eggs and young were per-
fectly safe. When returning from my vacation, I packed
many specimens of P.albolabris in a box of dead leaves;
in a small box I had several hundred eggs and very small young.
Several days elapsed before I could attend to them. I then pro-
cured a box, placing several inches of earth in the box, covering
it with dead leaves, and placed the larger shells on the leaves.
Then I busied myself with the eggs. Some that were just hatch-
ing, partly out of the shell, I reserved to put in alcohol. The
others I laid temporarily on a piece of paper in the box with the
larger shells. After putting the specimens in alcohol I returned
to the box, and was surprised to see several of the adults busily
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 249

engaged in devouring the eggs; but I attributed this to the fact
that many of the specimens, procured by me at the St Lawrence
river, owing to the exceedingly dry season, had been without food
for several weeks. I very much doubt that they are ever car-
nivorous when furnished with an abundance of vegetable food.
The immunity of the eggs and young in a box with more than a
hundred adult specimens would seem to prove this.

Since the above observations were made two years have
elapsed, and during that time I have raised many species, both of
Polygyra and Limax, from the egg to maturity and have
noticed no carnivorous habits, though some of the smaller forms
of Limax and Polygyra have been raised in the same box
as the large Limax maximus, and some of the latter had
a length of 4inches. In the same manner the smaller species of
Polygyra have been safely raised with P. albolabris.
The newly hatched young fed principally on the softer parts of
the dead leaves in the box, skeletonizing them.

I do not know the exact time elapsing between the laying and
the hatching of the egg, but it is certainly less than three weeks.
When on a visit to the St Lawrence river in August, I collected
several specimens and placed them in a box with moist earth
covered by dead leaves. When, three weeks afterward, I took
the specimens from the box, I found several groups of eggs, in
two of which the young were just emerging from the shell.

There seems to be no uniform time for the laying of the eggs.
I have had a large number of specimens in captivity for three
years, and at almost any time eggs and newly hatched young
could be found in the box. In some specimens collected in the
winter, while hibernating, well developed eggs were found in the
uterine canal.

Digestive system

The mouth is situated in the anterior part of the foot, and is
bounded by thick, fleshy lips (pl. 5, fig. 1). These lips are divided
into the upper, lower and lateral. The upper lip is composed of
five lobes or divisions situated side by side. The lower lip has
250 NEW YORK STATE MUSEUM

four divisions, of which the two lesser are situated above the two
larger divisions. The lateral lips are each entire, comparatively
large and somewhat crescentiform.

The mouth leads into an organ known as the buccal body (pl.
4, fig. 1). This organ is somewhat irregularly oval-shaped, and
contains the masticatory organ known as the radula (pl. 4, fig. 3).

Just within the upper lip is the crescentiform, corneous lamina,
known as the “jaw” (pl. 5, fig. 2), reddish brown in color, and
occupying the position of an upper jaw. On the outer face of the
jaw are 12 vertical ridges, with pointed ends, which project be-
yond the lamina. The ridges with their pointed ends closely
resemble teeth. The jaw is attached to the buccal body by a
band of muscular fibers, inserted in its upper convex edge. Dur-
ing feeding the jaw projects beyond the lips, which are protruded,
having the appearance of a prehensile proboscis, which takes
hold of the food and draws it to the mouth, the jaw cutting it into
small pieces, acting as a chopping knife.

The food now passes into the buccal body. A reference to the
figures on plate 4 will give a clear idea of the structure of that
organ. The outer walls are thick and are composed of constrictor
muscular fibers. On the floor of this organ are two gristly ele-
vations, known as the odontophoral cartilages, which have, at-
tached to their lower parts, small muscles arising from the side
walls of the buccal body. Resting on the odontophoral cartilages
is a cushion-shaped elevation, inclosed in a mucous membrane,
known as the odontophore. Overlying this is the lingual ribbon,
or radula, which is studded with an immense number, some fifteen
thousand, of small teeth or denticles, arranged in transverse and
longitudinal rows.

The teeth preserve the same form throughout in a longitudinal
line. The central line always differs from the others, and they
gradually vary in form and size, as they pass from the central
line laterally. The radula, or lingual ribbon, takes its origin in
the sac of the radula (pl. 4, fig. 3, 4), which projects from the
lower posterior part of the buccal body, continuing anteriorly
from the radular sac upward to the dorsal part of the buccal body,
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 251

then curving downward. It is connected by muscles with the
floor of the buccal body. Within the sac of the radula and im-
mediately anterior to it, the teeth are immature, in the posterior
part of the sac consisting of very minute papilla-like elevations,
each arising from a single cell. At the central part of the radula
the teeth or denticles are fully developed. Anteriorly they are
worn down, in some cases becoming smooth. During feeding the
radula is moved forward and backward by the action of the
muscles, acting as a rasp to triturate the food.

In addition to the muscles already mentioned, the following
muscles are connected with the buccal body (pl. 4, fig. 4, 14): the
buccal retractors, which have their origin, in common with the
tentacular muscles and the retractor muscles of the foot, at the
columella, and are inserted, as wide bands, in the posterobasal
and the posterolateral parts of the buccal body. Numerous small
muscles proceed from the buccal body to the integument of the
lips (pl. 4, fig. 1, 9). There are two delicate muscles proceeding
from the sides of the buccal body (pl. 4, fig. 1, 8), which, passing
forward and downward, are inserted in the cephalic integument.
Two broader bands of muscles, arising from the base of the buccal
body, below the muscles just mentioned, proceed laterally, and
are inserted in the integument (pl. 4, fig. 1, 7). A pair of very
delicate muscles arise from the posterolateral part of the buccal
body, and, passing along its sides, are inserted in the cephalic
integument (pl. 4, fig. 1, 6).

The esophagus takes its origin in the dorsal-posterior part of the
buccal body, and consists of a tube passing straight back between
the supra and infra-esophageal ganglia (pl. 4, fig. 1, 2, 4), the com-
missural cords connecting the ganglia bounding it. The eso-
phagus dilates and forms what is known as the crop. The mem-
brane of the esophagus, as well as that of the crop, is very thin,
and consists of a columnar epithelium and a basement membrane.

The columnar cells of the epithelium are long and pyramidal,
broad at the base and very narrow at their attached parts. They
are filled with fine, granular matter, and have each a nuclevlated
nucleus. Internally there are longitudinal folds of the membrane.
252 NEW YORK STATB MUSEUM

The crop is elongate oval (pl. 5, fig. 3, 4), having a diameter
three or four times that of the esophagus. Exteriorly it has a
somewhat plicated appearance, caused by the longitudinal folds
of the interior. It is situated in the first volution alongside of a
part of the spermatic duct.

On each side of the crop are situated the salivary glands (pl. 5,
fig. 3, 4). They are elongate, somewhat oval, and arborescent in
appearance. They extend nearly the entire length of the crop.
They are white in color, and under the magnifying glass present a
beautiful appearance. They are composed of lobules, which are
the dilated beginnings of the ducts, lined with cells oval in form
and having a nucleolated nucleus. The glands are connected
with the mouth by ducts, which extend alongside the esophagus.
They are cylindric and conspicuous (pl. 5, fig. 8).2

The stomach begins almost immediately at the termination of
the crop (pl. 5, fig. 3). At first it is small, but little greater in
diameter than the esophagus, but rapidly and regularly increases
in size nearly to its extremity. A transverse section is circular
in outline. The anterior part is situated in the first volution of
the shell, lying alongside the spermatic duct, continuing, having
on one side the larger lobe of the digestive gland, and the
albumen gland, on the other side being in contact with the herm-
aphroditic duct. It continues to the superior or smaller end of
the digestive gland and ovotestis, where it bends somewhat
abruptly downward and backward, giving origin to the intestine.
Its walls are apparently striated and very thin. The contents of
the stomach can be seen through the walls. For illustrations of
the crop and intestines see plates 5, 6, 10 and 14.

The intestine is of about the same diameter as the esophagus.
Immediately on leaving the stomach, it turns backward below
the stomach to the large lobe of the digestive gland, following the

 

1 According to A. B. Griffiths (Phys. invert. p. 109), the following constituents are
found in the salivary secretions: soluble diastatic ferment, capable of converting starch
into glucose, calcium, chlorin and doubtfully sulfocyanates and calcium phosphates. In
the branchiate Gasteropoda the latter two substances occur, as well as mucin, but
doubtfully chlorin.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 2538

lateral and posterior border of that gland, then, turning, it pro-
ceeds forward and downward on the outer part of the digestive
gland, approaching very closely to the first part of the intestine
at a short distance from the stomach; then, turning, it proceeds
upward and backward through the digestive gland to the border
of the pulmonary sac. In its course through the digestive gland
it forms an exaggerated letter S (pl. 5, fig. 3; pl. 6, fig. 7, 8).

The rectum continues along the border of the pulmonary sac
to the anus, which is situated near the respiratory orifice (pl. 5,
fig. 3, 8). On the outer side of the rectum, running its entire
length, is a band of muscular fibers, the function of which is, prob-
ably, to shorten the rectum and to assist in expelling its contents.

The digestive gland (pl. 5, fig. 3, 9), was formerly regarded as
analogous to the liver of vertebrate animals, but the organ con-
tains a diastatic ferment, which converts starchy matters into
glucose, and is comparable to the pancreas in vertebrate animals.
It contains neither biliary pigments nor biliary acids. The liver
of vertebrate animals is not a digestive gland in the true sense of
the word, since*neither the bile nor an infusion of the hepatic
tissues contains a digestive ferment. The name liver could not
therefore be appropriately applied to the digestive gland of the
Gasteropoda.

The digestive gland is divided into two parts, the larger and
inferior of which occupies the outer part of the volution imme-
diately beyond the heart and renal organ. The smaller and
superior lobe, in conjunction with the ovotestis, occupies the
apical whorls beyond the stomach.

In the digestive gland are innumerable ducts which unite
and form a large duct in each lobe of the gland, the three large
ducts uniting in one, which, in connection with the duct from the
superior lobe of the gland, enters the stomach at a short distance
from the beginning of the intestine.

The digestive gland is composed of lobules, which are formed
by the enlarged commencements of the ducts, and are lined with
254 NEW YORK STATE MUSEUM

polygonal cells, which become rounded on the removal of
pressure!.

Pedal gland

The pedal gland (pl. 4, fig. 4, 5), is situated in the middle of the
basal part of the foot. It is a spongy-appearing mass, extending
about two thirds the entire length of the foot, with a central cir-
cular passage connecting with the exterior by an opening im-
mediately below the mouth, and sending forth numerous ducts to
all parts of the basal portion of the foot. Its office is to secrete
the mucus or slime, which the snail so abundantly exudes while
moving, and which when hardened by the air presents a glassy

appearance.
enterochlorophyll
lecithin
oleic acid
In the alcoholic extract fatty acids
chlorin
, phosphoric acid
sulfuric acid
In the ethereal extract, a trace of fat
sugar
globules (coagulating at 66- C.)
glycogen
sinistrin
hypoxanthin
( potassium
In the aqueous extract boduita
calcium
magnesium
ash} iron (traces)
manganese
chlorin
phosphoric acid
U sulfuric acid
Dr Griffith (Phys, invert. p. 115) names the following substances as being found in
the digestive gland of the Pulmogasteropoda: diastatic ferments, pancreatin, peptones

 

and sodium.

 

1Dr Levy (Zezt. biol. 27: 398) has separated the following substances from the
digestive glands of Helix pomatia,
bo
ot
Ct

POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS

Generative system
Plates 7, 8

The Helicidae and Limacidae are hermaphroditic, and
the hermaphroditism is most complete, having complex male and
female organs separated from each other, but so arranged that
self-impregnation is impossible, the union of two animals being
necessary to reproduction.

The generative organs consist of the penis, vas deferens, sper-
matic duct, oviduct, uterine canal, albumen gland, hermaphroditic
duct, consisting of the fallopian tube and spermatic duct, and the
ovotestis. On the right side of the foot, about on a line with the
beginning of the superior tentacles, is an orifice known as the
genital orifice. It presents the appearance of a short slit with
the margins in contact, but is capable of great distension. It is
from this orifice that the penis is protruded during coition, and
into which the penis of the other animal is inserted. Leading
from this orifice is a short chamber or tube, known as the cloaca,
atrium, or genital vestibule, connecting with the penis and
vagina. The orifices of these two organs are situated side by side,
that of the penis immediately in front of the vagina.

The penis is a long, cylindric body of a glistening white color,
occupying the dorsal anterior part of the foot, nearly straight,
very slightly curved. Its walls are strong, thick and composed
of muscular fibers. At the base of the penis the walls are very
much thickened, and abruptly turned back exteriorly (pl. 8, fig.
1,2). The inner surface of the walls is plicated (pl. 8, fig. 3). The
lining membrane along the bottom of the penis is elevated into a
very strong muscular fold (the “ pilaster”), nearly filling the
interior of the penis (pl. 8, fig.3). The plications of the inner sur-
face of the walls are surmounted by papillae (pl. 8, fig. 4). The
plications of the lining membrane of the penis, and the muscular
fold as seen in the penis laid open longitudinally, and in the trans-
verse sections, under a low magnifying power or hand lens present
a very beautiful appearance.

The vagina and the spermatheca or receptaculum seminis are
256 NEW YORK STATE MUSEUM

connected with the genital vestibule, the origin of the vagina be-
ing immediately posterior to that of the penis. The vaginal body
is cylindrically oval in form, having a length of from two and one
half to three times the diameter. The walls of the vagina are
strong, thick, and consist of muscular fibers. Internally there
are a number of strong regular, longitudinal muscular elevations,
covered by a double membrane. Near the base these folds are pli-
cated, but become smooth above. At its extremity the vagina nar-
rows into a thin-walled tube or duct, which is of varying length,
sometimes short, at other times as long as the vagina. This
duct becomes dilated above, forming the receptaculum seminis.
The latter organ is elongate oval in form, having very thin walls,
and with minute longitudinal folds along the interior (pl. 8, fig.
10, 11, 14). These folds sometimes give a striated appearance to
the exterior. The organ is in contact with and closely adhering
to the oviduct.

During coition the penis is inserted in the vagina, and is there
closely held by the muscular walls and longitudinal folds, the
spermatozoa finding their way into the receptaculum seminis,
afterward passing down through the vagina, and fertilizing the
egg as it leaves the oviduct.

In addition to being a receptacle for the spermatozoa, the
receptaculum seminis, according to Dr Leidy! ‘‘ secretes a mucoid
matter, which probably facilitates the passage of the ova through
the cloaca. The mucus matter in the bladder is frequently found
to contain an immense number of an infusorial parasite, which I
have described under the name Cryptoicus.”?

Dr Leidy’s description is given at the end of the article on the
generative organs.

Ovotestis. The ovotestis, in common with the superior organ
of the digestive gland, occupies the apical volutions of the ani-
mal (pl. 7, fig. 1, 72). It is lighter in appearance than the digestive
gland, and is composed of a number of bundles or fasciculi of
short ceca. Each fasciculus is composed of numerous ceca, is

 

1 Terrestrial moll. and shells of the United States, p. 234.
2 Jour, acad. mat. sci, new series. v. I.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS =01

broadly pointed at the base, rapidly expanding, circular and con-
vex at the opposite extremity, having very much the appearance
of a composite flower. The ceca are sometimes simple, but usu-
ally bifurcate or trifurcate. The ceca of each fasiculus connect
with a tube, which in turn connects with a duct leading into the
hermaphroditic duct. Each cecum seems to have four walls, form-
ing an inner and outer chamber (pl. 7, fig. 7), a tube within a
tube. In the outer chamber or tube are produced the ova and
in the inner, the spermatozoa. f

The hermapbhroditic duct leads from the ovotestis to the uterus
and penis. It is an extremely convoluted organ, so twisted and
confused in P.albolabris as apparently to be composed of
short, cylindric, contorted tubes, agglutinated together. In
some other species of Helicidae and in Limax it is more
nearly straight, being flexuous, sometimes slightly folded or
spiral, but not convoluted. This duct is invaginated in the same
manner as the ovotestes, the outer tube carrying the ova and the
inner the spermatozoa.

Just before reaching the albumen gland the hermaphroditic
duct becomes constricted into a delicate thread-like tube. It
then enters an accessory gland, which is somewhat the form of a
cornucopia, the large end of which is composed of several folli-
cles. The gland rapidly narrows to its opposite extremity. It
is partially imbedded in the substance of the albumen gland.
Its purpose has not been clearly determined, though from the
size and persistency it is undoubtedly important. At the small
extremity of the gland the male and female organs become sepa-
rated, the fallopian tubes passing into the uterine canal, and
the epididymis continuing as a spermatic duct on one side of
the uterine canal (pl. 7, fig. 1, 9, and pl. 14, 22).

Albumen gland. The albumen gland, which is situated at the
extremity of the uterine canal, is a large boat-shaped or lingui-
form gland, of a yellowish color (pl. 7, fig. 1, 14). The walls of
the gland are composed of cells filled with albumen. The interior
of the gland is hollowed out by an elongate chamber or duct. The
function of the organ is to supply the ova with albumen.
258 NEW YORK STATE MUSEUM

The spermatic duct, as it proceeds along the uterine canal, is in-
vested with a yellowish mass, which has been called the prostate
gland. In structure it is composed of very closely packed, sim-
ple, tubular follicles, which are lined with pyramidal, epithelial
cells, containing at their base a nucleolated nucleus.

At the termination of the uterine canal the male and female
organs become entirely separated, forming the vas deferens and
the free oviduct (pl. 7, fig. 1, 6, 7, and pl. 14, fig. 1, 78, 19). The
vas deferens becomes enlarged, and for some distance assumes
a spiral or twisted form; it then contracts, becoming a long,
simple tube, somewhat folded on itself, in order to adapt itself
to the restricted space which it occupies. It continues to the
extremity of the penis, the walls of which are very thick and
muscular. The interior passage or duct is, for the greater part
of its length, trilobate in section. As it enters the penis it is
somewhat enlarged and the orifice is plicated. It is surrounded
by thickened lips and folds, which project into the penis. This
fold has a plicated membrane (pl. 8, fig. 6), resembling the mem-
brane of the fold of the penis previously described, and the outer
part is nearly in contact with that fold.

The urethra is situated between the lining membrane of the
penis and the membrane of the muscular fold (pl. §, fig. 2).

The retractor muscle of the penis is inserted in the vas deferens
at a short distance from the end of the penis (pl. 14, fig. 1, 17).

Uterine canal. The uterine canal is a large long tube or canal,
with plicated or sacculated folds. It is much greater in diameter
than the accompanying prostate gland. The walls are mostly
composed of polygonal cells, each cell having several nuclei
(pl. 7, fig. 1, 8 and pl. 14, fig. 1, 22). It is within this organ that
the eggs are completed.

Oviduct. The oviduct (pl. 7, fig. 1, 7, pl. 14, fig. 1, 20) is about
the same size as the twisted part of the vas deferens, and con-
tinues from the uterine canal to the vagina, entering that organ
near its mouth.

During coition the penis is everted, passing out of the genital
orifice, and entering the vagina of the second animal, coition con-
tinuing for several hours.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 259

The position of the generative organs in the animal can be
clearly understood from plate 23, figure 9.

The penis occupies the dorsal anterior part of the foot; the
vagina the anterior right lateral part. The receptaculum seminis
closely adheres to the prostate gland. The vas deferens is situ-
ated between and beneath the penis and vagina; on account of its
great length being disposed in irregular folds. The prostate
gland and uterine canal enter the first volution of the animal and
are disposed alongside the pulmonary cavity. The albumen
gland lies between the large lobe of the digestive gland and the
stomach. The constricted, thread-like part of the hermaphroditic
duct crosses the stomach from the base of the albumen gland,
and the convoluted part of the duct lies in the inner margin of the
volution, alongside of a part of the stomach. The ovotestis, in
conjunction with the superior lobe of the digestive gland, occu-
pies all the apical parts of the animal.

The generative organs of the other species of helicoid snails,
though varying in detail, are sufficiently similar to those of
P.albolabris to enable the student to recognize them with-
out difficulty, with the exception of those of Gastrodonta
intertexta, G. gularis, G. ligera and G. sup-
pressa, which species have accessory organs, that will be de-
scribed later on.

The vas deferens is usually about twice the length of the penis,
or less. In Polygyra exoleta it is longer, but in no
species, as far as I am aware, is it as long asin P.albolabris.
InP.tridentata andin P.exoleta it has the same form as
in P.albolabris, that is, enlarged, glandular, annulated or
somewhat spiral in appearance at its beginning; while, on the
contrary,inPyramidula solitaria it has this form atits
termination. InOmphalina fuliginosaitisfora great
part of its length expanded, so that its diameter is equal to that of
the penis.

In some species, as in Polygyra auriculata and
P. sayi, the penis is very long and bent on itself, while in others,
as Pyramidula solitaria, it is short, stout and clavate.
260 NEW YORK STATE MUSEUM

In Polygyra profunda the base of the penis is included
in a sheath formed by a continuation of a part of the genital
chamber, in the form of an inverted cone. In Circinar i a
concava it is long and cleft or bipartite at the summit.

The lining membrane usually has a number of rugae, longitudi-
nal and oblique. Sometimes, asin P.albolabris and Pyra-
midula alternata, there is one very large fold. In many
species, as in P.albolabris, the surface of the membrane is
papillated, but in some others it is smooth.

The vagina and receptaculum seminis vary in form. In the
greater number of species the vagina is not as large and muscular
asin P.albolabris, and the duct leading to the receptaculum
seminis is generally longer.

In Helix aspera and other European species there are
several accessory organs not found in P. albolabris or in
Limax. They are the flagellum, the dart sac and the accessory
mucous or digitate glands.

The flagellum is an elongated diverticulum of the penis and is
much coiled. The dart sac is an elongated, clavate, appendage
from the base of the oviduct. It has powerful muscular walls,
and contains in its interior the dart or spiculum amoris, attached
to a nipple-like protuberance at the bottom of the sac. The dart is
four-biaded, calcareous, and growing by the addition of calcare-
ous particles, deposited at its base from the vascular protuberance
to which it is affixed. If broken off it is speedily renewed in like
manner. Before coition the dart sac is everted from the genital
orifice, the dart thus becoming exposed. It is probably an excita-
tory organ.

The mucous or digitate glands, according to T. Rymer Jones,
“consist of a series of branched ceca, derived from two excretory
ducts, by which a milky fluid, secreted by the ceca, is poured into
the egg passage prior to its termination ”’. q

The receptaculum seminis of Helix aspera differs
greatly from that of P.albolabris and Limax maxi-
mus, consisting of an elongated duct, which subdivides into two
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 261

cecal diverticula, a longer and stouter coiled one, and a shorter
one with globular head, which during life is concealed in the first
coil of the intestine.

It is a remarkable fact that, while the flagellate form of the
penis, and the accessory organs, viz, the dart sac and multifid
vesicles, are very common in European species of Helix, they
are very rare in east American forms. A flagellate form of the
penis does not exist in a single one of the latter forms. An
analogue of the multifid vesicles exists in only four of the species
occurring in New York. In Gastrodonta intertexta
and G. gularis there is a single pair of follicles. InG.ligera
and G. suppressa there is but one short follicle. The dart
sac exists in the above-named species.

Description of a new species of entozoa
BY DR JOSEPH LEIDY

Plate 13, fig. 6

In September 1846 I first gave an account in our proceedings
of a new genus and new species of Entozoa, inhabiting the fluid
contained in the spermatheca of Helix albolabris, H. tri-
dentalis and H. alternata. Since then I have verified
the observation, and also have detected it in other species of
Helix, viz, elevata and thyroides, and have also de-
tected it in an allied genus, Bulimus decollatus. The
name which I gave it at that time I was not aware had been pre-
viously applied to a genus of Insecta brachelytra, with
the only difference of ihe latter having a neuter termination. I
will therefore change the name.

Cryptoicus minutissimus; forma mutabilissima; organisatione interno cellu-
larium et granulosum, C. h elicis. Coloris expers; forma plerumque elongata, fusiforme,
vel ovata; caudis duabus adversis, una longior quam altera. Structura interno sto-
machos duos et granulos numerosus parvos ,exhibit. Long ats —qh lin. Habitat
inspermatheca Helices albolabris, tridentata et Bulimusdecollatus.

This singular entozoon is a polygastric animalcule. Its varied
forms and movements are curious to observe; at one moment glo-
bulose, then oval, ovate, fusiform, sigmoid, crescentic, etc. It
appears as if it would outvie the kaleidoscope in its changes.
Sometimes it collects in bunches, adhering by the end of the
cauda to each other, and frequently it may be observed to contract
upon either of the large cellules, causing them to project beyond
262 NEW YORK STATE MUSEUM

the outline of the animal. The motions are vibratile rotary, with
a lateral progression, or whirling in circles like the insect Gy ri-
nus. Cryptoicus from its position might be mistaken for
the spermatozoa of the animal, but may be readily distinguished;
the spermatozoa of Helices having either a uniform sigmoid
or a spiral body, with an enormous proportionate length of tail,
and a slow vibratile motion.

Plate 13, figure 6, represents some of the varied forms of the
animal highly magnified.

Circulatory system

Method of injecting the blood vessels. I have found the follow-
ing method to be the best in obtaining a complete injection of the
circulatory system, and by it I have obtained the most beautiful
results, plainly showing all the minute ramifications of the arter-
ies and veins.

The necessary materials are an ordinary hypodermic syringe,
with as fine a needle as it is possible to obtain, the finer the bet-
ter; as an injection which would not pass through the finest
hypodermic needle certainly would not pass through the fine ar-
teries and veins. The distal extremity of this needle should be
blunt or slightly bulbous. A curved sewing-needle and very fine
thread are also necessary. As an injection fluid I have used and
found perfectly satisfactory Dr Seiler’s carmine gelatin. This is
sold by the ounce and comes in a solid mass.

A day or two before making the injection, some of the gelatin
should be placed in cold water in a wide-mouthed bottle. The
water will soften the gelatin. When it is proposed to use the
injection, the bottle can be set in a pan of hot water. Within
a short time the gelatin will be completely dissolved. It should
be thin enough when hot to enter easily the arteries and veins,
but of sufficient consistency to harden when cold. No rule can
be given as to the exact proportion of water and gelatin. The
right degree of fluidity must be determined by each student. Use
only filtered water with the gelatin, as a small particle of dirt in
the water might prevent a successful result.

Take the animal as soon after death as possible; wash away
the mucus. Then, as previously described, remove the shell,
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 263

wholly or till the heart can be plainly seen. The latter method
is, I think, preferable, as it avoids the danger of rupturing some
of the blood vessels, as sometimes happens when the entire shell
is removed. Cut through the peritoneum, alongside the rectum,
taking care not to injure the large vein which accompanies the
rectum; turn back the walls of the pulmonary cavity till the
heart is exposed. Using the curved needle pass a thread under
the ventricle. Place the animal in warm water, as hot as can
be comfortably borne by the hand, and before injecting be cer-
tain that the animal is thoroughly warmed through; also place
the syringe in hot water, having both the syringe and injecting
fluid warm. Draw some of the fluid into the syringe; then, hold-
ing the needle upward, expel a drop or two of the fluid, so as to
be certain that no air remains in the syringe. Leaving the animal
in warm water, with the point of an extremely sharp scalpel
make a slight incision in the walls of the ventricle just large
enough for the point of the needle to enter. Insert the needle,
bring the two ends of the thread together and tie them just back
of the point of the needle, to guard against the escape of the
injection through the incision. Some assistance would be useful
in this operation, as one hand will be occupied with the syringe.
Gently press the piston, slowly injecting the fluid, stopping im-
mediately when the injection is complete, as much pressure will
rupture the walls of the blood vessels.

Sometimes a very fine injection of the arteries can be made
by merely inserting the point of a hypodermic needle in the ven-
tricle, the rest of the process being as described above. But the
injection is liable to escape where the needle enters the wall of
the ventricle.

The injecting is a very delicate process, and partial, or even
a complete failure at the first attempt should not discourage the
student. The most frequent cause of failure is in not keeping the
animal and syringe warm enough, the injecting fluid rapidly hard-
ening in the blood vessels, preventing their full injection.

When the animal is fully injected, place it at once in cold
water; this rapidly hardens the gelatin. The remainder of the
264 NEW YORK STATE MUSEUM

shell can now be removed and the animal immediately dissected,
or it can be placed in alcohol for future use. The alcohol must
be at first very weak, gradually increasing its strength each day.

The advantage of a gelatin injection over a fluid one is that,
as the gelatin becomes hardened, dissections can be made with-
out danger of the escape of the injection from the severed blood
vessels. As the injection is a brilliant carmine, the blood vessels
stand out in bold relief from the light background of the various
organs.

Heart. The heart (pl. 9, 7, pl. 10, fig. 1, pl. 14, fig. 1, 30,
32) is situated in the outer portion of the first volution, just ante-
rior to the peristome, and is plainly visible from the exterior. Its
pulsations can be observed even through the shell. Ordinarily the
pulsations number about 45 or 50 a minute, in an adult indi-
vidual; but are variable, sometimes being much faster, and during
hibernation slower. In a young individual the pulsations seem to
be much faster, sometimes equaling 150 a minute. The heart con-
sists of a single auricle and ventricle, inclosed in an oval pericar-
diac sac. The ventricle and auricle are pyriform, placed base to
base, the bases being somewhat truncated. The ventricle is about

‘twice the size of the auricle.

In composition the walls consist of unstriped muscular fibers,
granulated, showing oval nuclei on the application of acetic acid.

The interior of the heart is lined with tesselated epithelium,
consisting of granulated cells. The interior of the walls of the
aorta have a similar structure.

The wall of the pericardium is very thin and transparent. The
pericardial fluid is very abundant, and, according to Dr
Leidy, is sometimes inhabited by an entozoon, named by him
Distoma vagans! Between the auricle and yentricle is a
valve, so disposed as to permit the passage of the blood only from
the auricle to the ventricle.

Arteries (pl. 9, fig. J). The apex of the ventricle gives origin
to one large aorta, which almost immediately subdivides, one
branch proceeding posteriorly, and supplying the digestive gland,

 

1Jour. acad, nat. sci. new series. v. i Philadelphia.
POLYGYRA ALBOLABRIS AND LIMAX MANIMUS 265

hermaphroditic duct, stomach, ovotestis and albumen gland; the
other and larger of the two proceeds anteriorly, supplying the
remaining organs of generation, muscles, crop and all the organs
contained in the foot.

The posterior aorta passes on the outer part of the inferior lobe
of the digestive gland, giving off numerous branches to this gland,
the intestine and also to the albumen gland. Just after giving off
this latter branch, it crosses a portion of the stomach, and for a
short distance disappears in the substance of the lobe of the diges-
tive gland; then emerging it continues along the lower inside edge
of the volution to the apex of the animal, giving off branches to
the superior lobe of the digestive gland, and to each of the fasci-
culi of ceca composing the ovotestis.

The anterior aorta, at a short distance from the heart, gives off
a branch to the stomach. On the stomach this branch subdivides
into two branches; each of which gives off numerous branches,
covering the stomach with their ramifications. This artery, before
reaching the stomach, gives off a branch, which continues to the
hermaphroditic duct.

.At a short distance from the branch to the stomach is a large
branch, which continues on the surface of the prostate gland and
uterine canal, giving off numerous small branches to these organs.

At a short distance beyond this branch is another, which shortly
subdivides; the larger of the two divisions continuing to the mus-
cular collar, and supplying blood to it, and to the adjacent parts.
The smaller of the two divisions continues with the retractor mus-
cles of the foot. From the larger of the two subdivisions a branch
is given off, which continues to the crop, supplying the crop and
the overlying salivary glands. A small branch continues with
each salivary duct to the buccal body.

The main aorta continues, without branching, to the infra-
esophageal ganglia, where it suddenly turns downward and back-
ward, continuing posteriorly in the base of the foot. Just at
the turn it gives off three branches, which proceed directly
anteriorly; the central and largest of which supplies the buccal
body. The two lateral ones, which are very minute, proceed
266 NEW YORK STATE MUSEUM

to the cephalic integument. A branch is also given off, which
proceeds alongside the nerve to the muscular collar. Branches
also accompany the commissural cord, forming a complete
circle. From this, on the left side, arteries proceed to the
tentacles; from the right side an artery proceeds, which subdi-
vides; one branch proceeding to the penis, the other to the vagina;
these organs being covered by numerous ramifications. From the
artery near the ganglia proceed the arteries supplying the ten-
tacles of the right side.

Veins. The arteries break up into smaller and smaller branches,
and finally into a network of capillaries, that meet a similar net-
work leading to the veins, which empty into large veins or sinuses;
the principal ones of which are three in number. The first begins
in the apex of the volutions, receiving the veins from the superior
lobe of the digestive gland, continuing on the outer edge of the
volution to the beginning of the pulmonary chamber, receiving in
its course several large veins. These divide, one division passing
along the edge of the pulmonary chamber, alongside the rectum
to the thickened muscular collar, passing along the inner edge
of this to the base of the pulmonary chamber. The other division
passes along the base of the pulmonary chamber, uniting with the
first described division at the muscular collar, forming a sinus
completely incircling the pulmonary chamber, and known as the
circulus venosus pulmonis, or pulmonary circulus.

The arteries of the foot, as in the visceral part of the body, break
up into capillaries, that enter the capillaries of the veins, which
empty into a large vein or sinus, situated below the pedal gland.
From this sinus proceed numerous veins, which finally connect
with the pulmonary circulus. s

From the pulmonary circulus arise many veins, which form a
large vein leading to the heart, and known as the pulmonary vein.
These veins are known as the efferent veins. They alternate with
much regularity with a series of veins leading from the pulmonary
vein, but intimately connected with the efferent vessels, which are
known as the afferent veins (pl. 11, fig. 1-4).

Circulation. The circulation is as follows: the blood leaves
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 267

the heart by the aorta, and is distributed by the arteries to the
different parts of the body, and passes from the minute branches
of the arteries into a flexus of capillaries spreading over the
whole body; passing from them into the veins, and from the veins
into the sinuses previously described; finally all the blood enter-
ing the pulmonary circulus; and thence the pulmonary veins,
where, circulating freely through efferent and afferent vessels, it
becomes thoroughly aerated.

The renal organ or kidney is supplied with blood, which has
previously been aerated, but only a small part of the blood
passes each time through it.

Though the veins are situated in the substance of the body,
and their walls are much thinner than those of the arteries, they
are not simply lacunae or wall-less passages in the body, as they
have frequently been described. The walls though thin are dis-
tinct.

Blood. In animals of the simplest structure all the fluids seem
to be of the same nature and seem to be “only water charged
with organic particles, but in animals higher in the scale of
being the fluids cease to be of the same nature, and there is one,
distinct from all others, destined to nourish the body. This fluid
is the blood. It not only nourishes the body, but is the source
from whence is derived all the other secretions, such as saliva,
urine, bile, ete.”

In the higher animals the blood is of a red color; but in the
Invertebrata it is of different densities and of various colors.

The blood of the Helix and Limax consists of a nearly
transparent fluid in which float solid corpuscles.

For the following facts in regard to the composition of the
blood I am indebted to Dr Griffith’s Physiology of the Invertebrata.

In the majority of the Invertebrata the carrier of oxygen to the
tissues is haemocyanin, contained in the blood, but in many of the
Annelida, as well as in nearly all of the vertebrates, the transport
of oxygen from the surrounding medium (air or water), to the
living tissues is made by the hemoglobin of the blood. This sub-
stance, as is well known, forms an oxygenized condition which is
very unstable, and which is carried by the blood across the tissues
of the animal, and is there dissolved, yielding its oxygen to those
tissues which require it.
268 NEW YORK STATE MUSEUM

In Gasteropoda, as well as in Cephalopoda, Crustacea and
Arachnida the function of respiration is brought about by an
albuminoid substance analogous to hemoglobin, but containing
copper instead of iron, this substance, which Fredericq names
haemocyanin, forming a very unstable combination.

The saline matter contained in the blood of the Helix is
about 1.0752; in Limax about 1.1152.

Touching the color of the blood, Mac Munn! says in regard to
the blood of Helix pomatia: “It assumes a distinct blue tint
on exposure to the air, and gave no absorption bands, but ab-
sorbed a little of the violet end of the spectrum. On treatment
with ammonia its color was not so well marked, and it had a
partially reddish tinge, but no bands could be seen, and after,
treatment with acetic acid did not remove the color.”

One time I drowned 12 individuals of P. albolabris,
leaving them, as usual, in the water about 48 hours. The blood
in the arteries of all these specimens had coagulated and turned
a dark purple black in color, so that the course of the arteries
could be as distinctly traced as if they had been injected. JI am
unable to account for this phenomenon, as of scores of specimens,
treated in the same manner, these were the only specimens
coagulated and colored, though the others were kept in the same
box and fed on the same kind of food.

Nervous system

The nervous system (pl. 12) consists of five distinct sets of
ganglia, and four ganglionic swellings, and the commissures con-
necting them or proceeding from them. The principal ganglia
are the supra-esophageal, the infra-esophageal, consisting of two
sets, and the two buccal ganglia. The ganglionic swellings, or
ganglia, are situated at the extremity of the tentacles. The
ganglia corresponding to the one situated on the dorsal surface
of the stomach in Limax maximus I have not observed in
Polygyra.

When the animal is extended, the supra-esophageal ganglia
are situated just above the esophagus, immediately posterior to

 

1 Quart. jour. micro, sci, 1885
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 269

the buccal body, but varying somewhat in position according to
the degree of contraction of the body.

The infra-esophageal ganglia are situated below and just pos-
terior to the buccal body, and are connected with the supra-
esophageal ganglia by a double commissure. The buccal ganglia
consist of two small masses, situated just below the surface of
the posterior dorsal part of the buccal body. They are connected
with each other and with the supra-esophageal ganglia.

The esophageal ganglia and the connecting commissures are
enveloped by an essentially opaque sheath, and it requires very
careful manipulation te remove this so as to determine the form
of the ganglia. This is best effected by two small needles fixed in
the end of small round sticks, as described on page 241, using
one in each hand. The points of the needles should be inserted
just below the surface of the sheath, and a little of it torn away
with each insertion, being very careful not to introduce the needle
far enough to penetrate the ganglia beneath. The fine forceps,
mentioned on page 241, will be found useful in removing the
loosened parts of the sheath. In this operation it is necessary to
proceed very slowly. Any undue haste will almost certainly
result in the destruction of the ganglia.

The supra-esophageal ganglionic mass, before the removal of
the sheath, has the appearance of a single quadrangular mass,
wider than. long, the posterior margin incurved. The double com-
missures proceeding from the posterolateral extremities, appear
as single large, flattened nerves. When the sheath is removed,
the supra-esophageal ganglionic mass is seen to be composed
of two sets of ganglia, connected by a commissural cord, the
ganglia of each set being aggregated together, the two ganglionic
masses being precisely similar in detail. The principal one of the
supra-esophageal ganglia (pl. 12, a) is subquadrangular or sub-
ovate in outline, about two and one half times as long as wide,
slightly constricted at the middle. Attached to the lower outer
part of this ganglion is a smaller ganglion, about one fourth the
size of the preceding one. Attached to the posterior part of these
ganglia are three comparatively small, nearly round ganglia (pl.
270 NEW YORK STATE MUSEUM

12, a), so aggregated as to have, on a superficial examination, the
appearance of an oblong mass.

The infra-esophageal ganglia have, before the remoyal of the
sheath, the appearance of a flattened, circular mass, with a
central opening through which passes a large artery. When the
sheath is removed, it is seen that the ganglia form two masses
aggregated together, making a sub-circular mass. The upper
mass is composed of five subovate ganglia, of nearly equal size
(pl. 12, b). One is situated dorsally and centrally, and two on
each side of this one. The lower part consists of two larger ovate
ganglia, joined to each other and to the ganglia above them.

The buccal ganglia are small, somewhat kidney-shaped bodies
(pl. 12, n).

The ganglia of the superior tentacles are subpalmate in form,
the palm being unduly developed, and the fingers very short (pl.
12, e).

The ganglia of the inferior tentacles are pear-shaped (pl. 12, %).

The commissures connecting the supra and infra-esophageal
ganglia are of equal size. The upper commissures proceed from
the posterior part of the outer supra-esophageal ganglia, and are
connected with the anterior part of the lower ganglia of the upper
part of the infra-esophageal ganglionic mass (pl. 12, c). The lower
commissures proceed from the outer ones of the small, nearly
round ganglia of the supra-esophageal ganglionic mass, and are
connected with the lowest two ganglia of the infra-esophageal
ganglionic mass, or, as they are sometimes designated, the pedal
ganglia (pl. 12, ¢).

From the inner anterior part of the principal Supra-esophageal,
or cerebral ganglia, proceeds a large, conspicuous nerve, which
connects with the ganglia at the extremity of the superior or ocu-
lar tentacles (pl. 12, d, e). This nerve, after entering the tentacle,
gives off a nerve which proceeds to the eye, the optic nerve
(pl. 12, f, g); also from the outer anterior part of each ganglia a
nerve proceeds to the mouth and adjacent integument. .

From the central anterior part proceed two very delicate nerves
which continue to the integument of the superior tentacles,
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 271

From the lateral ganglia of each mass proceed two very con-
spicuous nerves; the inner one (pl. 12, 1), continuing to the mouth,
the outer one continues anteriorly, branching; one branch (hk)
going to the mouth and adjacent parts, the other (i), continuing
to the ganglion at the extremity of the inferior tentacles.

The nerves previously described give off branches to the anterior
part of the body, also to the penis and vagina.

From the lower inferior part of the principal ganglion proceeds
a commissural cord (0), connecting with the buccal ganglion.

The anterior extremities of the buccal ganglia are connected by
a commissural] cord.

From the buccal ganglia nerves pass off: first, two nerves, ante-
riorly, to the surface structure of the buccal body; second, two
branches, which penetrate posteriorly into the buccal body; third,
a branch accompanying the salivary duct to the salivary gland;
fourth, a branch to the esophagus; fifth, a nerve to the anterior
part of the buccal body.

From the infra-esophageal ganglionic mass proceed the follow-
ing described nerves: from the dorsal ganglion a very conspicuous
nerve (p), which takes the same general direction as the cephalic
artery, continuing alongside the uterine canal. At the point where
the arteries give off branches to the muscles and the crop the nerve
passes through the loop thus formed, and also gives off branches
both to the muscle and to the crop. It then continues, slightly
diminished in size, along the uterine canal to the albumen gland.
The main part continues along the albumen gland; a branch ac-
companies the hermaphroditic duct to the ovotestis, giving off
filaments to the stomach and digestive gland. Another branch pro-
ceeds to the heart and renal organ. From this branch a smaller
branch proceeds to the adjacent parts of the digestive gland. The
nerve is easily traced to the digestive gland, but from that point
the nerves are very fine, and careful study is necessary to distin-
guish them.

From each of the two ganglia adjacent to the dorsal one, a very
large nerve passes to the muscular collar (r); bifurcating just be-
272 NEW YORK STATE MUSEUM

fore entering the collar, one branch passes through the muscles,
the other continuing in the pulmonary chamber.

From the inferior part of the lateral ganglia proceed five nerves

mn each side (uw), continuing to the integument.

From the pedal ganglia proceed two large nerves, running nearly
directly backward and parallel to the central part of the base of
the foot, giving off several branches. From the pedal ganglia
there are about 12 other nerves, supplying the base of the foot.

The ganglia are composed of cells or globules, varying very
much in size, round or polygonal from mutual pressure, having a
nucleus which occupies one half or two thirds the globule. The
nucleus has several transparent nuclei. The nerves consist of
bundles of tubuli. The walls of the tubuli are transparent.

Special organs of sense

Touch. The sense of touch is extremely acute in every part of
the foot; the integument and base of foot being liberally supplied
with nerves. The tentacles are specially sensitive, but I have not
been able to touch any part of the foot so lightly that it was not
iiimediately felt by the animal. In motion the animal depends
more on the sense of touch than on eyesight.

Taste. There is no doubt that the animal possesses some sense
of taste, but, from long observation, I think that in the selection
of food the animal depends more on the sense of smell than that
of taste.

Light. The eyes of both Helix and Lima-x are situated at
the extremity of the superior tentacles, and are conspicuous, hav-
ing the appearance of bright, black specks. Under a low power
can be seen the globular eyeball invested by a transparent tunic,
corresponding to the cornea; the crystalline lens lying under the
delicate cornea; the choroid, which forms two thirds of a sphere,
transparent and having a single layer of irregularly round or oval,
black pigment cells. Polygyra is nocturnal in its habits, and
perhaps at that time it can see more clearly; but in all my experi-
ments with different individuals, many of them conducted with
only sufficient light to distinguish the animal, I have seen no evi-
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 273

dence that Poly gyra is possessed of sight, with the single ex-
ception that young individuals placed on a table, by a window,
seemed to crawl away from the light, but in adult individuals the
light did not seem to make any difference. I have very frequently
moved a stick or some bright object directly in front of the ex-
tended tentacles, as the animal was moving, but with no effect
whatever. Often J have observed the animal running directly into
an object, withdrawing its tentacles and changing its course only
when the tentacles touched the object.

Smell. That the snail possesses olfactory organs admits no dis-
pute, but the location of these organs has been a matter of doubt.
J have had many snails in captivity for three years, and. I have fre-
quently experimented with them to determine what degree of
olfactory sense they possess. After leaving them without food for
several days, I have put in one corner of the box a small head of
lettuce, concealing it by a few of the dead leaves. In a short time
the snails would appear from under the leaves, and on the surface
would raise the anterior portion of their bodies in the air, with
extended tentacles, turning from one side to the other, having ex-
actly the appearance of a quadruped sniffing the air in the en-
deavor to locate some object. Having decided on the position of
the lettuce, they would invariably move directly toward it, and
this sometimes from a distance of 18 inches. J have repeated this
experiment again and again but always with the same result. It
was impossible for the animals to see the lettuce on account of the
screen of leaves, and, as previously asserted, I am satisfied that
their power of vision is extremely limited, at least by daylight or
by artificial light.

The discrimination in regard to food must be due also in a
great degree to the sense of smell. I have placed in my box of
snails young beet leaves, spinach and other tender vegetables,
which it would naturally be supposed would be acceptable to the
snails; but they invariably refused to eat them, though deprived
of other food, and in no case were these articles even tasted, show-
ing, I think, that they were rejected on account of their odor.

It being admitted that they possess olfactory organs, it remains
274 NEW YORK STATE MUSBHUM

to locate them. Dr Leidy! and Dr Sochaczewer,? believed that the
olfactory organs are situated in the pedal sinus.
The latter author made the following experiment:

Having cut off the tentacles of Helix pomat ia, the wound
was allowed to heal. The snails were then placed on a flat plate,
the edge of which was smeared with turpentine; both the muti-
lated and unmutilated specimens turned away from the edges;
this shows that the tentaculae are not the seat of the olfactory
organs.

I do not think that this experiment is at all conclusive, or in
fact has any bearing on the matter, as the foot both of Helix
and of Limax isso extremely sensitive that on the first contact
with any substance smeared with turpentine the animal would
turn quickly away; the effect being essentially the same as if the
animal had come in contact with heated metal. The fatal defect
of this experiment is that the sensitiveness of the foot was not
taken into consideration. I have tried the same experiment as
far as surrounding the animals with turpentine, but they never
turned away till they came in contact with the turpentine. If
they turned away on account of the smell, they would do so before
touching the turpentine.

If one observes a snail, when in motion, it will be seen that the
superior tentacles are usually held, essentially, in one position,
occasionally striking an object, apparently not seeing it; but the
inferior tentacles are constantly in motion, and are bent down
toward the object on which the animal is moving, but not touch-
ing it. Taking into consideration the limited power of sight, it
seems to me that the snail must be assisted by the sense of smell.

That these tentacles have an important function to serve is evi-
dent from their anatomic character. <A large nerve proceeds from
the principal of the cerebral or supra-esophageal ganglia, which
connects at the extremity of the tentacle witha very conspicuous
ganglionic swelling (pl. 18, fig. 4, 5), which gives off numerous
nerve fibers to the extremity of the tentacle. That the tentacles
are not tactile organs is evident from two facts; first, they would

 

1Terrestrial moll, and shells of the United States,
2Zeitschrift fiir Wiss. zoologie. 35:133.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 275

be unnecessary, as the foot is well supplied with nerves, and is
very sensitive; second, though the tentacles are bent down toward
the object on which the animal is moving, I have never seen them
touch the object. Furthermore, the tentacular ganglia are anterior
to all others, with the single exception of the ganglia of the super-
ior tentacles, and are attached by their nerves to the cerebral
ganglia, which, taken in connection with the anterior position of
the tentacles themselves, corresponds to the position of the olfac-
tory organs in vertebrates. When the tentacle is withdrawn, the
olfactory sense still exists; the olfactory organ then closely cor-
responds to the olfactory organ of fishes. Negatively, the olfac-
tory organ certainly does exist; but the nerves at the mouth,
which have been considered by some authors as olfactory nerves,
are undoubtedly nerves of taste; while the pedal sinus is clearly
for the secretion of mucus, which the animal so abundantly.
exudes while in motion. Taking into consideration the anatomic
details of the inferior tentacles, and innumerable observations of
the use of these organs by the animal, I have no hesitation in
affirming that they are olfactory organs.

In some forms of Gasteropoda no tentacles exist, and it will be
interesting to determine whether in the absence of tentacles the
olfactory sense is deficient. In relation to this Albany Hancock,!
says:

Being engaged at present in the investigation of the anat-
omy of some members of this family, my attention was naturally
directed to this point, and I think that I have obtained satisfac-
tory proof that these hornless animals have really the sense of
smell highly developed. The head lobe in the Bullidae is, in fact,
nothing else than the dorsal (superior) and labial (inferior) ten-
tacles fused in one continuous mass. ‘This Cuvier asserted long
ago; and it can be very easily proved on anatomical grounds

It may therefore suffice to say at this moment, that
the nerves which supply the oral (inferior) and dorsal (superior)
tentacles in the Gasteropoda go to this lobe, the former to the

anterior and the latter to the posterior portion of it; a pretty clear
proof of its real nature.

Hearing. The so-called auditory organs consist of two trans-

 

1 Ann. and mag, nat. hist. 1852.
276 NEW YORK STATE MUSEUM

parent vesicles, situated beneath the sheath of the supra-esopha-
geal ganglia, one on each side, placed immediately on the gang-
lia and connected with nerves proceeding from the cerebral
ganglia. They are extremely minute, and are filled with a trans-
parent fluid, containing a number of small bodies, composed of
concentric layers of carbonate of lime, frequently hollow at the
center, called otoliths. During life, and for a short time subse-
quent, these bodies have a peculiar vibratory motion.

The size and situation of these bodies, and their nerves, would
naturally lead to the conclusion that as auditory organs they
would be of little, if any, use. As with Anodonta, I have
tried numerous experiments to test 'the sense of hearing. Any
noise which does not jar the animal, has no effect on it. And
I have no hesitation in saying that the sense of hearing, if ever
possessed, has been lost.

These remarks apply both to Polygyra andto Limax.

Sense of direction. Snails in common with most animals, with
the exception of man, have what has been called the sixt e;
that of direction or locality. I had for several months a large
box, containing about one hundred snails, in one corner of my
library. At the time I was making sections of shells to illustrate
this work. J one day examined the snails in the box, and picked
dut three which were to all appearances dead. These I took out
for the purpose of making sections of the shell. Not having time
then, I laid them on the window ledge, in the opposite corner of
the room, about 12 feet from the box. Several hours later I
looked for them, and, not finding them, thought they had been
accidentally brushed from the ledge. Looking on the floor for
them, I noticed the peculiar, glass-like trail made by a snail while
moving. Then, examining carefully the spot where I had laid
them, I found that, though apparently dead, they were alive, and
I easily traced the three snails by their trails, which led in an
absolutely straight direction to the box in which they had been
kept, and I found them under the edge of the mosquito netting,
which had been tied over the box, as near to the interior of the
box as it was possible for them to reach. Afterward I experi-
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 277

mented several times by placing individuals in various parts of
the room, and once in another room. They almost invariably re-
turned to the box.

LIMAX MAXIMUS L.

The animal has a thick vermiform body, with a broad, ribbon-
like pedal disk, having very much the appearance of the so-called
foot of the Polygyra. The mouth, tentacles, etc., are situated
as in that genus. The anterior part of the body is rounded. The
posterior is acute and dorsally keeled.

The mantle is situated on the anterior dorsal part of the body,
and is somewhat shield-shaped. The anterior margin is rounded;
the posterior margin angular. It consists of a thick, fleshy mem-
brane. The anterior part is free from the body, and, when the
animal contracts, the head is concealed beneath it, the mantle
coming down before the head like a inask. The posterior part
is not movable. It contains the rudimentary shell, and covers
the pulmonary chamber, heart and renal organ.

The respiratory orifice is situated on the right side of the man-
tle, about midway of its length; the mantle being notched or
curved around the orifice. :

The genital orifice is situated anteriorly on the right side as in
Polygyra.

The body is divided into two cavities; the smaller containing
the pulmonary chamber, the heart, renal organ, and a part of the
rectum, the larger containing the digestive and reproductive or-
gans, the nerve ganglia and the principal muscles. ~

Limax differs from Polygyra in that all the organs are
contained in the vermiform body, corresponding to the foot of
Polygyra, and in being possessed of only a flat, rudimentary
shell. Polygyra resembles a Limax “ with the greater por-
tion of the mass squeezed out on the back, and arranged in a
turbinate manner”, and covered by a shell.

The integument consists of a thick mucous membrane, with a
muscular substratum, as in the foot of Polygyra. Itis nearly
uniformly developed, but is thickest on the mantle, tail and pedal
278 NEW YORK STATE MUSEUM

disk. On the head and upper part of the body, anterior to the
tentacles, it is very thin.

The mantle and body have black markings, which vary in inten-
sity on different individuals. .

Digestive system
Plates 15, 16

The esophagus is very short, and has a diameter of about .6
mm. It leads into the crop, somewhat abruptly expanding to a
width of about 4 mm and: continues essentially in a straight line
for nearly three fourths the length of the body, slightly dimin-
ishing in diameter. It then contracts, quickly expanding to
nearly its former diameter, to form the stomach, continuing for
about one fifth the length of the previous part, gradually dimin-
ishing in size, then turning abruptly forward and ending in a
position nearly parallel to the constricted part.

The intestine leaves the posterior part of the stomach, and
proceeds anteriorly through the digestive gland, where it turns to
the left, and, making a broad curve in the gland, again proceeds
anteriorly, in contact with the previously described portion for
a part of the distance; then, turning to the right, it forms a loop
over the retractor muscles, near their origin; again proceeding
posteriorly on the dorsal surface of the crop, nearly to the con-
strictor of that organ; again abruptly bending forward and con-
tinuing in contact with the last described part, passing under the
pulmonary chamber, terminating at the anal aperture near the
respiratory orifice.

The latter two convolutions are oblique to the crop and lie on
its dorsal part. In nearly all the specimens which I have ex-
amined they are empty and flat, even when all the other parts of
the intestine are filled with the remains of food. They are very
unlike the rest of the intestine in appearance. Their abrupt
turning backward and simultaneous decrease in size, and their
dissimilarity in appearance to the rest of the intestine are very
misleading, and it requires careful dissection to show the contin-
uity with the rest of the intestine, as they greatly resemble a
cecum.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 279

Salivary glands. The salivary glands are situated on the anterior
part of the crop, the one dorsally and the other latero-ventrally.
They vary in shape and size (pl. 28, fig. 5, 6) the dorsally situated
one being the smaller. They consist of numerous lobuli, which
are conglomerate. From each gland proceeds a conspicuous duct,
which enters the buccal body, one on each side of the esophagus.

Digestive gland. The digestive gland consists of three principal
lobes, divided into lobules. It, in conjunction with the ovotestis,
occupies the posterior part of the animal, and also invests the
greater part of the stomach, and the posterior lateral part of the
crop. See plate 15, figure 3, for its position, and plate 23, figures a
and 8, for its form.

Generative system
Plates 15, 17

The general appearance of the generative organs is the same as
in Poly gyra, varying only in details, with the exception of the
ovotestis.

The penis and anterior part of the other organs pass obliquely
over the anterior part of the crop (pl. 15, fig. 2), a part of the ute-
rine canal and spermatic duct lying ventrally and to the left of
the crop. The ovotestis is situated at the posterior end of the
animal, on the dorsal part of the digestive gland.

The penis is a long, cylindric body, comparatively much longer
than in Polygyra albolabris. The posterior end is
curved and bent on itself. It is destitute of the outer fold or
so-called prepuce existing in P. albolabris.

The retractor muscle of the penis is long and inserted, together
with the vas deferens, on one side slightly anterior to the ex-
tremity.

When exserted, a thin, erect membrane is shown extending
backward from the meatus; and also membranous folds at the
meatus.

The vagina and receptaculum seminis are much smaller than in
P.albolabris.

The vas deferens is short, its length being equal to or less than
280 NEW YORK STATE MUSEUM

that of the penis. For about one half of its length it 1s thickened,
annulated and glandular, becoming cylindric and filiform, enter-
ing the penis on the side, just anterior to the extremity.

The uterine canal is conspicuous, but does not present so dis-
tinctly a sacculated appearance as in P. albolabris.

The albumen gland is large, flattened, rounded at each extrem-
ity, broadest at the anterior, gradually diminishing to the pos-
terior.

The hermaphroditic duct is short, flexuous, but not convoluted,
asin P.albolabris.

The ovotestis consists of an oval, flattened mass, formed by an
aggregation of ceca. It is nearly four times as long as wide; situ-
ated on the dorsal part of the posterior end of the digestive gland.
It differs greatly from the ovotestis of Polygyra.

Circulatory system
Plates 18, 19

Heart. The heart is situated at the lower left side of the
pulmonary chamber. It consists of a single auricle and ventricle,
each pyriform, placed base to base, the bases being truncated.
The auricle is anterior to the ventricle and about one half its size.

Arteries. The aorta (pl. 18, fig. 1) proceeds from the apex of the
ventricle, and almost immediately divides into two principal
branches, the anterior and posterior of about equal diameter.
The aorta divides before leaving the pulmonary chamber, giving
the appearance of two aortae proceeding from the heart.

The anterior artery proceeds for a short distance laterally, then
anteriorly. It supplies the stomach, salivary glands, penis, recep-
taculum seminis, buccal body and nerve ganglia. At the gangli-
onic mass it turns abruptly backward, and proceeds along the mid-
dle of the ventral part of the animal, immediately above the pedal
sinus; continuing for about one half the length of the animal, then
bifurcating and entering the foot.

Where the artery bends forward a large branch is given off to
the crop. This branch almost immediately subdivides, the princi-
pal branch procecding anteriorly on the dorsal part of the crop.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 281

Near the esophagus it bifurcates, a branch proceeding to each of
the salivary glands, and anterior part of the crop. In its progress
to the anterior part of the crop it gives off four branches, two on
each side of the crop. These branches in turn give rise to numer-
ous others.

The second principal branch (3’), proceeds posteriorly for some
distance, giving off comparatively few branches.

At the subdivision of the anterior and posterior crop arteries
there are two smaller branches (4, 3”), the first of which proceeds
to the uterine canal, the second directly to the ventral part of the
crop, giving off several branches principally posteriorly.

At the ganglionic mass, where the aorta turns downward and
backward, a branch continues forward under the buccal body (13),
giving off small branches to the buccal body, muscles, lips, etc.
Branches from the anterior artery accompany the commissural
cords connecting the two principal ganglionic masses, forming a
complete circle, asin P.albolabris (14), giving off branches to
the tentacles (15).

Just previous to its turning backward the anterior artery puts
out a branch, which subdivides and supplies the penis and vagina
(11, 12).

The posterior aorta gives off branches to the stomach, intestine,
digestive gland, uterine canal, hermaphroditic duct, ovotestis, etc.
he first branch follows the course of the intestine, entering a lobe
of the digestive gland, and ramifying through it. Very near this
the artery gives off a branch, which proceeds along the hermaph-
roditic duct to the ovotestis. Two small branches have previously
been given off to the hermaphroditic duct. Several small branches
are now given off to the intestines at frequent intervals.

From the opposite side of the artery a branch proceeds to the
upper attenuated end of the principal lobe of the digestive gland,
giving off numerous branches throughout the lobe.

The next branch continues along the outer surface of the large
lobe of the digestive gland, giving off numerous branchlets, which
ramify throughout the lobe.

Immediately after the anterior artery bends abruptly toward the
282 NEW YORK STATE MUSEUM

anterior portion of the animal, the large artery, which supplies
the stomach, gives origin to a comparatively large branch to the
digestive gland, and gives off numerous branches, both to the
intestines and digestive gland. The next branch proceeds from
the same side of the artery, continuing to the digestive gland,
giving off numerous branches and finally forming a network in
the lobes of the digestive gland (pl. 18, fig. 9).

The next branch is from the opposite side of the artery, and con-
tinues on the posterior part of the stomach. This branch is prom-
inent. At about one half the distance from the artery to the ven-
tral part of the stomach it bifurcates, one branch again bifurcat-
ing; one branch containing latero-anteriorly and the other dorso-
anteriorly. The main branch continues to the ventral part of the
stomach, bifurcating; the branches continuing mainly on the ven-
tral part of the stomach.

The next prominent branch is from the opposite side of the ar-
tery. The principal artery of this branch continues to a lobe of
the digestive gland, and ramifies through it; a smaller branch con-
tinues to the intestine.

The next conspicuous artery is from the large artery which sup-
plies the uterine canal and the so-called prostate gland.

Pulmonary cavity. The pulmonary cavity lies below the mantle
aud is of essentially the same shape. It is situated immediately
below the shell cavity, and contains the heart, renal organ, the
posterior part of the rectum and the anus. It is separated from
the visceral cavity by the muscular peritoneum or diaphragm.

The respiratory orifice is situated on the right side of the body,
at the edge of the mantle (pl. 28, fig. 1, 1). This orifice opens and
closes at regular intervals; the normal respiration seems to be
from 16 to 18 times a minute, though it is frequently variable.
When open the orifice is circular, and is closed by muscular fibers
which surround it.

The pulmonary veins, or rete, are situated mostly on the roof of
the cavity. They are numerous, anastomosing, and occupy nearly
the whole surface (pl. 19, fig. 2).

Veins. The veins are situated mostly in the substance of the
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 283

body, not being on the surface as is frequently the case with the
arteries. Asin P. albolabris, they are not simply lacunae or
spaces in the body, but have a distinct wall.

The branches of the arteries grow smaller and smaller, and
finally consist of an anastomosing network, which communicates
with a similar network of veins; these capillaries gradually coal-
escing, forming larger branches, which combine to form large
veins, connecting with the sinus of the pulmonary cavity. There
are two veins parallel with, and in close contiguity to the pedal
gland or sinus.

The two largest veins are situated in the integument of the sides
of the body, one on each side. They are connected with the ar-
teries by innumerable ramifications. They are illustrated on plate
18, figures2 and 3; but only the large vessels are shown, thesmaller
ones not being represented. There are also smaller veins in the
lateral anterior parts of the integument, and a large vein in the °
dorsal part of the integument.

‘The blood proceeds from the heart through the arteries,entering
’ the veins from the arteries, and carried by them to the renal organ
aud the pulmonary cavity, where it is aerated, and returned by the
large pulmonary veins to the auricle, thence to the ventricle.

Kidney. The kidney is situated in contiguity to the heart (pl.
19, fig. 3), and is a large subovate, glandular organ. From the
lower right side proceeds a duct, which continues along the lower
part of the pulmonary cavity to the rectum, continuing along-
side of this; curving near the extremity, the parts of the curve

being in apposition to the rectum, and opening in close contiguity
to the anus.

Nervous system
Plate 22

The two principal ganglionic masses are the supra and infra-
esophageal (1, 2).

The supra-esophageal ganglia are situated above the esopha-
gus, and just posterior to the buccal body, when the animal is
extended. Of course when the animal is contracted the relative
positions are altered. The ganglionic mass consists of three pairs
284 NEW YORK STATE MUSEUM

of ganglia; the three pairs being united by an extremely short
broad commissural cord, which is very inconspicuous; the inner
pair of ganglia having somewhat the appearance of coalescing.

The outer pair are larger than the others and somewhat ob-
scurely kidney-shaped. The anterior margin being rounded and
continuous; the posterior part being bilobed, the inner lobe larger
than the outer.

The second, or median, pair of ganglia are in contact with the
inner part of the first mentioned pair for their entire length.
They are curved, broadest at the base, and tapering to a point,
very narrow at their widest point.

The third, or inner, pair are nearly in contact at their anterior
part, gradually diverging posteriorly. They are comparatively
narrow, though twice the width of the second pair, and are about
four times as long as wide. They are each obscurely divided into
four lobes, of which the anterior is subtriangular, the posterior
nearly round, and the remaining two subquadrangular.

The infra-esophageal ganglionic mass is much larger than the
supra-esophageal, (2), and consists of six pair of ganglia, aggre-
gated more or less in one mass.

With the exception of the first pair the ganglia are regularly
bilaterally arranged; one of each pair being on opposite sides of
a median line.

The first pair consist of a large and a small ganglion, the
larger one being ovate with a length about equal to twice its
greatest diameter. Immediately anterior to this is a small
ganglion, about one third the size of the first mentioned ganglion.

The next pair are situated one on each side, and partially un-
derneath the first pair. They are subovate in form and are about
one and one half times the size of the first mentioned pair.

The next pair are each about the size of the first mentiqned
ganglion, and are oval or subovate in form, and are situated
mostly underneath the second pair, their anterior ends projecting.
The posterior ends of the second pair project, laterally, beyond
the third pair.

The fourth pair are subovate in form and situated beneath the
second and third pair.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 285

The fifth pair are situated below the fourth pair. Their inner
margins are nearly in contact.

The large cephalic artery passes through the ganglionic mass,
bounded above and below by the third and fifth pair of ganglia,
and laterally by the fourth pair.

The sixth pair are below the fourth and fifth pair of ganglia,
and when the ganglionic mass is viewed from above are almost
hidden from sight.

The ganglionic masses are connected by two pairs of commis-
sural cords, the upper ones of which proceed from the second pair
of the supra-esophageal ganglia, and continue to the under part
of the fourth pair of infra-esophageal ganglia. The inferior pair
of cords proceed from the posterolateral part of the lower lobe of
the inner, or third pair of supra-esophageal ganglia, and continue
to the lower part of the sixth pair of infra-esophageal ganglia.

Two smaller ganglia are situated near the dorsal surface of the
posterior part of the buccal body, one on each side of the esoph-
agus, just as it leaves the buccal body. They are comparatively
small, a little less than three times as long as wide, and are
divided into three nearly equal lobes, (3) the anterior one being
broader and shorter than the other two, which are nearly round.

The two ganglia are connected by a strong commissural cord
proceeding from the posterior lobes.

The buccal ganglia are connected with the cerebral ganglia by
two commissural cords, which proceed from the under surface of
the inner pair of cerebral ganglia, to the outer and under part
of the anterior lobes of the buccal ganglia.

There are ganglionic swellings in the extremities of both the
superior and inferior tentacles. That in each superior tentacle is
digitate in form, the palm being exaggerated in size and the
fingers short. From each of these processes, or fingers, numerous
fibers proceed to the thin integument at the end of the tentacle.
The ganglia of the inferior tentacles are pyriform, the largest end
being nearest to the extremity of the tentacle, and giving off
numerous fibers to the extremity of the tentacle.

A small ganglion is situated near the first branching of the
286 NEW YORK STATH MUSEUM

aorta on the dorsal part of the stomach. It is subovate in form,
gradually enlarging from its posterior to its anterior extremity,
and is about four times as long as wide (4).

From the outer anterior part of the principal ganglia proceeds
a stout nerve to the extremity of the superior tentacle (5).
Within the tentacle this nerve gives origin to a slender nerve
proceeding to the eye, the optic nerve. From a point closely
contiguous to the first mentioned nerve, but nearer to the anterior
margin, proceeds a nerve, smaller than the first, which near the
anterior extremity of the animal bifurcates, one branch going to
the mouth (7), the other to the ganglia at the extremity of the
inferior tentacle (6). From a point slightly nearer to the anter-
ior margin proceeds a nerve, which near the mouth bifurcates
and gives off nerves to the mouth and adjacent parts of the in-
tegument (7’). From the anterior lobe of the inner ganglia nerves
proceed to the muscles and integument of the superior pair of
tentacles (8). From the inner part of the principal ganglia pro-
ceed commissural cords, which unite with the anterior lobe of the
buccal ganglia (3’).

The posterior lobes of the buccal ganglia are united by a short,
broad commissural cord (3”).

From the anterior lobe of each buccal ganglion arise two
nerves, which proceed to the anterior part of the buccal body,
giving off numerous branches (9).

From the inner part of each median lobe arises a nerve which
continues posteriorly alongside the esophagus (10); and from the
posterior lobe two nerves, which supply the posterior part of the
buccal body (11).

The cephalic artery passes through the infra-esophageal gang-
lionic mass, the ganglia forming a ring, and in an uninjected
specimen might easily be mistaken for a large nerve.

From the posterior part of the dorsal ganglia proceed five
nerves, three of which are of nearly equal diameter; the other two
are smaller. The one to the left is free for a short distance, then
buries itself in the substance of the retractor muscles, continuing
to the origin of the muscles in the muscular layer.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 287

The median nerve is directed posteriorly to the right (21, 21’),
and furnishes nerves to the pulmonary cavity, respiratory orifice
and anus.

The nerve from the right of the ganglion continues posteriorly
to the large artery, entering the foot, to a minute oblong gang-
lion (4). The ganglion gives off five nerves, of which the larger
arises in the outer anterior part, and proceeds along the intestine
in close contiguity to the artery.

Immediately anterior to this is a small nerve proceeding to the
pulmonary cavity.

From the opposite anterior part proceeds a nerve supplying
the hermaphroditic generative organs.

From the posterior part proceed two nerves supplying the
stomach and digestive gland.

In the inferior part of each of the second pair of infra-esopha-
geal ganglia arises a large nerve which passes posteriorly and
outward, entering the integument just anterior to the pulmonary
chamber; the branches of these nerves supplying that organ and
the heart.

From the posterior part of these ganglia proceed two very
large nerves, which continue to the postero-basal part of the
animal, parallel to and at a short distance from the pedal gland,
giving off several branches to the base of the foot (12, 13’, 13”).

In the inferior part of the other ganglia arise five other pairs
of nerves (15-19), which are inserted in the integument at the
sides; and other more numerous nerves, which are inserted in the
foot.

Muscular system

Plates 19, 20

The principal muscles, viz, the retractor muscles of the anterior
part of the body, the buccal body and the tentacles, have their
origin in the inner muscular layer, just posterior to the pulmon-
ary cavity on the right side.

They at first consist of two broad, flat, somewhat connected
bands (pl. 19, fig. 1, 2). At about one half the distance to the
nerve ganglia these bands are subdivided, giving origin to the
288 NEW YORK STATE MUSEUM

ocular tentacular muscles (3), and the retractor muscles of the
buccal body (5). The superior, or ocular tentacular muscles,
shortly subdivide, giving origin to the muscles of the inferior, or
olfactory tentacles (4), which are much smaller than those of the
ocular tentacles.

The muscular sheath of the supra-esophageal ganglia is con-
nected with the superior tentacular muscles by two flat muscular
bands on each side (pl. 20, fig. 1, 2).

In 'the anterobasal part of the animal arises a set of three
muscles on each side (pl. 19, 20, fig. 1), the posterior one (Z) arising
under the muscles of the superior tentacle, and inserted near the
lips of the animal. The middle one (8) is inserted in the muscles
of the inferior tentacle. The anterior and largest muscle (9)
passes over the superior tentacle muscles and is inserted at the
mouth.

Posterior to these a muscle on each side has its origin in the
basal part of the animal, and is inserted in the muscle of the in-
ferior tentacle (10).

In figure 2, plate 20, the retractor muscles have been cut close
to the buccal body, and that organism has been turned forward
to show its under side, and also the base of the anterior part of
the body cavity.

On each side of a basal median line, and at a short distance
from it, a thin, flat band of muscular fibres arises, which is in-
serted at the extreme anterior end of the body at the mouth, im-
mediately below the anterior end of the buccal body (1). These
two bands of muscles, at their anterior part cross each other at
an angle of about 45°. Their function is to contract the basal
part of the anterior portion of the body.

On each side of the buccal body the lower part of the lateral
lips can be observed, showing as a white mass, somewhat regu-
larly longitudinally divided. From the posterior part of each
mass proceed two muscles, one broad, the other narrow, uniting
with the muscles of the inferior tentacle (pl. 19. fig. 2, 3).

On the right side of the figure the lip and its muscles are shown
in their natural position; on the left side of the figure the lip and
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 289

its muscles, as well as the muscle of the inferior tentacle, are
turned forward in order to show a short, broad muscle, which has
its origin in the anterior basal part of the body, and is inserted
principally in the muscles of the inferior tentacle, but some of the
fibers are inserted in the large muscles of the lip (pl. 20, fig. 2, 4).

On the under side of the buccal body, toward the posterior part,
are several moderately broad, horizontal bands of muscles, which
are partially concealed by overlying longitudinal muscles (10).
Bands of muscles are situated on the ventral surface of the
buccal body, proceeding from the posteroventral part and diverg-
ing to the sides (6). Strong bands of muscles originate in the
middle ventral part of the buccal body, and, slightly diverging,
are inserted in the anterobasal part of the animal, just under the
anterior part of the buccal body (5). A band of muscles is
situated on each side of the buccal body, proceeding from the
posteroventral to the anterolateral part of the buccal body (7).

Numerous fibers have their origin in the anterior part of the
buccal body, and are inserted in the integument of the mouth.
The entire outer walls of the buccal body are composed of mus-
cular fibers, both transverse and longitudinal.

Looking down on the buccal body, the following muscles can
be observed: a pair of delicate muscles, one on each side, arising
in the inferior posterolateral part of the buccal body, and in-
serted in the cephalic integument; another delicate pair arising
in the anterolateral part of the buccal body, and inserted in the
integument, near the-base of the inferior tentacles; a pair which
proceed laterally from’the anterior basal part of the buccal body,
being inserted in the integument each side of that body.

The integument or skin of the animal is composed of two layers,
the inner of which is composed of interlaced muscular fiber; and
the viscera are inclosed by a very thin muscular peritoneum.
The first layer is composed of unstriped muscular fibers, ar-
ranged transversely, longitudinally and obliquely.

The peritoneum is composed of muscles arranged transversely
and longitudinally, and gives rise to the retractor muscles pre-
viously described.
290 NEW YORK STATE MUSEUM

EMBRYOLOGY OF LIMAX MAXIMUS

When the ova have reached a certain stage of maturity they
leave the ovary. This process is known as ovulation. They pass
through the hermaphroditic duct (pl. 16, fig. 1, 10), to the albumen
gland (9), and thence to the oviduct (7); from which they are dis-
charged, that is, laid.

The composition of the egg is as follows: in the interior of the
egg is the germinative vesicle, or egg nucleus, which contains a
still smaller vesicle, or germinative dot; surrounding these is the
yolk, which is a liquid of varying consistency. In the snail it is
transparent. These parts of the egg are formed in the ovary.
The albumen surrounds the yolk, and in the case of Limax is
semitransparent, less so than the yolk. This substance is not
formed in the ovary, but is secreted by the albumen gland (pl. 16,
fig. 1, 9). The albumen is surrounded by a membrane, which in
Limax is semi-transparent, so that, when the egg is viewed
under the microscope by transmitted light, the movements of the
embryo can be observed, though not distinctly enough for study.

In the eggs of the Polygyra the outer covering is still
membranous, though much thicker than in Limax, and it is
opaque. After the escape of the young Polygyra, it has very
much the appearance of a calcareous shell.

Soon after fertilization the egg undergoes the process of seg-
mentation, that is breaks up into cells. It first divides into four
equal cells; and then smaller cells are formed from the division of
the first four, so as to lie outside of them. The smaller cells now
subdivide and spread over the first four. The cell mass is dilated,
becoming hollow. The large cells subdivide and sink into the
hollow of the sphere, forming an elongated groove, the origin of
which at the surface is known as the blastopore. This orifice
subsequently closes up. The invaginated cells, formed by the
subdivision of the large cells, are known as the endoderm. The
outer layer, formed by the division of the smaller cells, is known
as the ectoderm. This condition of the egg forms the gastrula
stage (pl. 24, fig. 10-14).

A dilatation of the ectodermal walls now takes place, a con-
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 291

siderable space being left between the ectoderm and endoderm
(pl. 25, fig. 6 and succeeding figures).

The body of the animal as first observed consists of a slight
swelling of the upper side of the cell mass (pl. 25, fig. 7).

In the following descriptions it must be remembered that the
ventral surface of the animal is uppermost.

The swelling above mentioned very soon shows a tendency to
divide into twu parts (pl. 25, fig. 9, and pl. 24, fig. 17), the anterior
part of which is the foot proper, the posterior part the mantle,
shell sac, etc.

Even at this early stage the embryonic shell can be observed,
consisting of a few dark colored crystalline plates, not yet united.

At this stage the mouth appears at the position formerly occu-
pied by the blastophore; which has disappeared or been closed,
and consists of an invagination of cells, bounded by lateral lips
(pl. 24, fig. 20).

The shell sac and mantle enlarge much the faster proportion-
ally, as shown in plate 25, figures 11, 12.

In figure 12, and more distinctly in figure 18, the development
of the tentacles is shown, which at this stage have the appear-
ance of flat circular disks.

The body is very small; from its extremity a circular setsi-
transparent appendage, the podocyst, is developed, consisting of
two walls, which are connected by reticulated muscular cells.
The body now rapidly develops, as shown in figures 15 and 16,
plate 25.

The shell has also increased in size, consisting of numerous crys-
talline plates, not yet united.

The ectodermal sac and podocyst have also increased in size.
The surface markings are now apparent, and the beating of the
heart is plainly visible beneath the mantle.

The smaller tentacles, the lateral lips of the mouth, the odon-
tophore and the beginning of the alimentary canal have appeared;
the pedal sinus is also apparent.

At this stage (pl. 25, fig. 17-21), the ectodermal sac and podo-
cyst have reached their greatest development, and hereafter
gradually diminish in size till completely absorbed.
292 NEW YORK STATE MUSEUM

The podocyst is now an object of great beauty, to which no
drawing can do justice. It undergoes a rhythmic movement of
dilatation and contraction, sometimes being so expanded as to
include the rest of the embryo, then contracting to less than one
half that size. The ectodermal sac also undergves a similar con-
traction and expansion, sometimes in harmony with, and again
alternating with that of the podocyst.

The whole embryo, from the stage represented by figure 11, has
a rotatory motion.

In the stage represented by figure 19, I have first observed the
‘primitive kidneys.” They are situated on each side of the en-
doderm, and consist of a series of curved elongate cells, within
which concretions are developed, and terminate in a duct (pl. 28,
fig. 4).

The cells proper are apparently angular or of different shapes
(pl. 28, fig. 1, 2); but this is due to mutual pressure, as when the
sac is ruptured the cells flow out perfectly spherical, as shown in
figure 3.

As development proceeds a movement of the cells takes place
from the ectodermal sac into the constantly enlarging body (pl. 26,
fig. 1). The alimentary canal accompanies the cells; the anus
alone remains in its original position.

In the stage represented by figure 5, plate 26, the ectoderm so
closely bounds the endoderm as not to be apparent. The ectoder-
mal cells have been largely absorbed into the body, or, rather,
changed into body tissue, and the podocyst is very much reduced
in size. The tentacles are assuming their mature form, and the
mouth and lips are very distinct. The intestine is nearly com-
plete and the larger endodermal cells have, in great part, been
converted into the substance of the digestive gland. The respira-
tory orifice, the mantle and shell are well formed.

Heretofore the embryo has been represented with the ventral
part uppermost, but in figure 2, plate 27, it is represented, in a
reverse position, as in adult condition.

In this stage the endodermal cell mass has been almost entirely
changed into the alimentary canal and its appendages, the podo-
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 293

cyst has been almost entirely absorbed, and the various organs
are approaching their perfect condition. Figure 1, plate 27,
represents the appearance of the embryo in the egg capsule at this
stage (8). The absorption of the podocyst continues for a short
time longer, when the animal becomes completely formed and
emerges from the egg.

A careful study of the figures on plates 24-28, and their explana-
tions, will perhaps show more clearly the development of the
embryo than the preceding text.

It occasionally happens that there are two ova in one egg cap-
sule, and in one instance I have observed four embryos in one
egg capsule (pl. 27, fig. 4, 5).

\

Time of laying eggs

In the latter part of September I had a number of specimens
sent to me. Within a very few days a majority of them laid
eggs. Of course the very short time of confinement, only two or

not lay their eggs till the middle of November, when naturally
they would have been hibernating for a month. It would seem

 

 

therefore that some of the animals lay their eggs in the fall, and
others not till the following spring.

The eggs are laid on the surface of the ground, under dead
leaves, logs, stones, or any sheltered space, where the requisite
moisture can be obtained. They are laid ina cluster. The num-
ber in the clusters observed by myself varied from 50 to 180. They
are soft and before leaving the animal must be very much coin-
pressed; for a mass of eggs occupies a larger space than the ani-
mal itself. When first laid they are of beautiful appearance,
semi-transparent, resembling globes of liquid. Light transmitted
through them becomes a beautiful golden color. They are
usually round, but sometimes oval, and wlien they are in apposi-
tion a part is frequently pressed in till it is concave, but, as the
embryo grows, this part is pushed out, the egg becoming regularly
round or oval.

It would seem probable that all eggs laid at the same time
294 NEW YORK STATE MUSEUM

would hatch out at about the same time, but I had several clusters
of eggs laid within 24 hours of each other, kept in the same box,
and necessarily under the same conditions, and when some of
these were hatched out, the embryos of other clusters were not
more than half developed. This statement has been questioned,
but I am absolutely sure of the correctness of my observations in
this respect.

Several of the clusters had not been fertilized, as shown by the
non-development of the embryo.

Binney declares that eggs that had been several times subjected
to a great heat in an oven, so as to become perfectly dry and
shriveled, when placed in a moist place regained their lost form,
and young were produced from them. While not doubting this
statement, my experience has been that, when the egg became
dry and shriveled, the embryo was killed; though when supplied
with moisture the vitality under adverse circumstances was
wonderful.

Embryos that I have dissected from the egg and placed in water
retained life from 24 to 48 hours. Even when the power of
motion was lost, the heart continued to beat.

Rate of growth

Even under the same conditions the rate of growth of all the
animals is not uniform. I have at this writing more than 100
animals that were hatched at about the same time. They have
been kept in the same box and of course under the same > condi-
tions. But they vary decidedly in size, ‘some > being not more than
half the size of others.

At least two seasons are required for an animal to reach
maturity. I have now specimens that were hatched nearly 10
months ago, which have been kept in a warm room during cold
weather, therefore not hibernating, and supplied with an abund-
ance of food; yet some of them are not half grown. They prob-
ably developed as rapidly as in natural conditions. Naturally
they would hibernate during cold weather, and the growth would
not be as great in 10 months as in confinement.
oH

POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 29

EXPLANATION OF PLATES

Polygyra albolabris

PLATE 1)
FIG.
1-3 Dorsal, profile and ventral views of an adult shell, natural

size. ;
4 A profile view, showing a more flattened form than in
fig. 2.

5,6 Ventral and profile views of a young shell, the peristome
being as yet unformed.

7 Ventral view of an adult shell, showing the form of the
under side of the peristome.

8 Profile view of a shell just after leaving the egg, x 10, the
perpendicular line to the left of the figure showing the
natural size. Figures 9, 10 and 11 are also enlarged, the
perpendicular lines to the left of the figure showing the
natural size as in fig. 8.

9-11 Showing succeeding stages of the form of the shell before
reaching maturity.

12 An adult shell.

13 In this figure a part of the lower volution of the shell is
broken away to show the interior.

14 A section of a shell. The outer part of the shell is ground
away in order to show the columella.

15 A section. The columella has been ground down to show
its interior.

PLATE 2
Fic.
1 An egg natural size and enlarged.

2 A view showing the shell within the egg.
3 A view showing the shell emerging from the egg.

4 Dorsal and profile views of a shell, newly hatched, natural
size and enlarged.
296 NEW YORK STATE MUSEUM

5, 6 Profile and ventral views of a shell about one month old,
natural size and enlarged.

Dorsal and lateral views of a shell about three months
old, natural size.

8,9 The same, x 3.
10 Surface of the shell, x 10.
11 The same, x 20.

“1

12 Transverse section of the prismatic layer of the shell, x 100.
13 A section of a part of the peristome, x 40.
14 A section of the peristome and a part of the shell, x 10.

15 A section of the shell; cuticle; outer layer; median layer;
inner layer.

16 A section of the volutions, x 2.
17 One volution more highly magnified, x 6.

18 A transverse section of the peristome, x 2.

PLATE $3
Fic.
1 Dorsal view of a shell and extended animal. The smaller

figure represents a newly hatched animal. Both figures
are natural size.

bo

Profile view of shell and extended animal, natural size.

oo

An animal from which the shell has been removed, show-
ing protruding penis; 7 penis; 2 anus: 3 stomach; 4 oyo-
testis; 5 intestine; 6 digestive gland; 7 kidney; 8 pulmon-
ary vein.

IN

The same view as in figure 3, the volutions being partially
uncoiled to show the position of the generative organs.
For explanation of the organs see plate 23, figure 9.

5 Ventral view, the animal being retracted within the shell;
1, respiratory orifice.

for)

Laterobasal surface of the integument, x 6.

~

A part of the integument of the dorsal part of the foot, x 6,
-1

POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 29

PLATE 4
Fic.

1 The buccal body, enlarged, from above; 1 the buccal body;
2 esophagus; 3 salivary ducts; 4 nerves uniting cerebral
and buccal ganglia; 5 retractor muscles; 6 depressor mus-
cles; 7 levator muscles; 8 protractor muscles; 9 labial
muscles.

2 The buccal body. The dorsal wall is cut through, and
separated, displaying a part of the interior; 1 buccal
body; 2 muscular wall of the buccal body; 3 lateral lips;
4 vadula, or lingual ribbon; 5 sac of radula; 6 esophagus;
7 salivary duct.

3 The buccal body laid open, from above ; 1 lateral lips; 2
muscular wall of the buccal body; 3 odontophoral carti-
lage; 4 radula; 5 sac of radula; 6 retractor muscles.

4 Longitudinal section of the buccal body; 1 odontophoral
cartilage; 2 radula; 3 sac of radula; 4 muscular wall; 5
jaw or dental plate; 6 esophagus; 7, 8 muscles connected
with the radula; 9 opening of the pedal sinus; 10 pedal
sinus; 11 muscular sole of animal; 12 infra-esophageal
ganglia; 13 supra-esophageal ganglia; 14 retractor mus-
cles; 15 tentacular muscle.

5 A section of the animal showing: 1 pedal sinus; 2 large
veins; 3 small veins; 4 mucus glands; 5 muscular sole
of foot.

6 Perpendicular section of the buccal body; 1 esophagus; 2
salivary ducts; 3 lingual ribbon or radula; 4 sac of
radula; 5 odontophoral cartilage.

7 Vertical section, the same as figure 6, the esophagus, etc.,
have been removed, bringing into view the radula; 1
radula; 2 odontophoral cartilage.
298 NEW YORK STATE MUSEUM

PLATE 5
Fig.
1 A view from the under side of the head, showing the mouth

and lips, x 5.
2 The jaw, x 10.

3 The digestive organs; 1 the buccal body; 2 esophagus; 2’
the crop; 3 salivary ducts; 4 salivary glands; 5 stomach;
6 intestine; 7 rectum; 8 anus; 9 digestive gland; 10 ducts
of digestive gland; 11 ventricle; 12 auricle; 13 pericar-
dium; 14 kidney or renal organ all x 2.

4 Crop and salivary gland, x6.

5 Heart and kidney as seen from the exterior.

PLATE 6
Fic.
The lettering on each of the figures refers to the same organ.

1-6 Transverse sections of the body from the buccal body to
near the posterior extremity of the foot.

1 genital opening; 2 penis; 2’ sac of radula; 3 esophagus; 4
salivary duct; 5 tentacular muscles; 6 vas deferens; 7
peritoneum; 8 pedal sinus; 9 oviduct; 10 vagina; 11 uter-
ine canal and spermatic duct; 12 the mantle.

7 The stomach and a part of the intestine as seen from above.

8 The stomach as seen from below, showing also the ducts of
the digestive gland and their connection with the stom-
ach.

PLATE 7

Generative organs
Fia.

1 i genital aperture; 2 penis; 3 outer fold or prepuce; 4
vagina; 5 receptaculum seminis; 6 vas deferens; 7 free
oviduct; 8 uterine canal; 9 spermatic duct; 10 talon, or
accessory gland of the hermaphroditic duct; 11 hermaph-
roditic duct; 12 ovotestes; 13 retractor muscle of the
penis; 14 albumen gland, all x 3.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 299

Fig.
2 An enlargement of a part of the generative organs: 1 her-

maphroditic duct; 2 talon; 3 albumen gland.
Accessory gland, or talon, seen from above, x 6.
The same as seen from below, x 6.
The ovotestes, x 5.

The cecal tubes of the ovotestes, x 30.

Aa ano fF Ww

A transverse section of the ceca of the ovotestes, showing
the spermatic within the ovarian tube, x 30.

PLATE 8
Fia.
1 An exterior view of the penis, x 3.
2 A longitudinal section of the penis, showing the corrugated
fold, or pilaster, of the interior, and the manner of the
formation of the outer fold, or prepuce, x 3.

3 The penis opened from the dorsal part, showing the corru-

gations of the lining membrane, and the corrugated fold,
pilaster, of the membrane, x 3.

4 A part of the corrugated and papillate lining membrane,
x10.

5 A transverse section of the vas deferens, x 6.

6 A tranverse section of the vas deferens, showing its en-
trance into the penis, x 6.

7-9 Sections of the penis, figure 9 being beyond the pilaster,
x 6.

10 An exterior view of the vagina and receptaculum seminis,
x4.

11 A longitudinal section, showing the muscular folds of the
vagina, x 4.

12 A transverse section of the vagina, and of the oviduct at its
entrance into the vagina, x 6.

13 A transverse section of the vagina at the point indicated by
the dots in figure 11, x 6.

14 A transverse section of the receptaculum seminis, x 6.
300 NEW YORK STATE MUSEUM
PLATE 9
Arteries

Circulatory system, 1 auricle; 2 ventricle; 3 posterior aorta;
4 anterior aorta; 3’ artery to albumen gland; 3” artery
to digestive gland; 6 artery to stomach; 7 artery to her-
maphroditic duct; 8 artery to uterine canal and sper-
matic duct; 9 artery supplying muscular collar, pedal
muscles and crop; 10 artery to pedal muscles; 11 artery

- to muscular collar; 12 artery supplying crop; 13 arteries
to salivary ducts; 14 artery to base of foot; 15 artery
supplying nerve commissures; 16 arteries to the tenta-
cles; 16’ artery to buccal body; 17 artery to vagina; 18
artery to the penis; 19 artery to the intestine; 20 artery
to the ovotestes.

PLATE 10
Fie.

1 1 Pericardial cavity; 2 auricle; 3 ventricle, x 6.

2 Showing the stomach and under or inner face of the digest-
ive gland, and the arteries supplying that part of the ani-
mal: 1 auricle; 2 ventricle; 3 stomach; 4 intestine; 5 ducts
of digestive gland; 6 artery to the smaller or superior
lobe of the digestive gland; 7 arteries to the ovotestes;
8 kidney; 9 rectum; 10 digestive gland, x 3.

3 The outer part of the digestive gland and its arteries.

The numbering has the same signification as in figure 2.

>

The stomach and its arteries, x 3.

or

The crop and salivary gland and their arteries, x 3.

o

Showing the arteries of the ceca of the ovotestis.

PLATE 11
Fic.

1 An enlargement showing the heart and the veins of the
pulmonary cavity: 1 auricle; 2 ventricle; 3 the large pul-
monary vein leading to the auricle; 4 the afferent veins;
5 the efferent veins; 6 the large vein or venous sinus in-
circling the pulmonary cavity.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 301

Fig.
2-4 Figures showing the position of the pulmonary cavity, in

relation to the volutions of the animal.

PLATE 12
Nervous system

@ supra-esophageal or cerebral ganglia; 6 infra-esophageal
ganglia; c commissures connecting the supra andinfra-esophageal
ganglia; d nerves to the ocular or superior tentacles; ¢ ganglionic
enlargement at the extremity of the ocular tentacles; f opticnerve;
g eye; h nerves to olfactory, or inferior, tentacles; + ganglionic
enlargement at the extremity of the inferior tentacle; k nerve to
mouth; J, m nerves supplying the mouth and adjacent parts; 1 buc-
cal ganglia; 0 commissural cords connecting the supra-esophageal
and buccal ganglia; p nerves supplying the generative system and
the visceral mass; 7 nerves to the muscular collar and pulmonary
cavity; s nerves supplying the basal parts of the animal; ¢ nerves
supplying the laterobasal parts of the foot; u nerves to the integ-
ument on each side.

PLATE 13

The same lettering refers to the same muscles in each figure,
Fie.

1-2 The retractor muscles of the buccal body, foot and tentacles
enlarged. 7 retractor muscles of the buccal body; 2 re-
tractor muscles of the foot; 3 retractor muscles of the
ocular tentacles; 4 muscles continuing to the lips and ten-
tacles; 5 muscles of olfactory tentacles; 6 muscles of
mouth; 7, 8, 9 muscles of the buccal body; 7 levator
muscle; 8 protractor muscle; 9 depressor muscles. Figure
1 shows the muscles as seen from above; figure 2 is a
lateral view.

3 An enlarged section of the tentacles: 7 integument; 2, 2’
tentacular muscles; 3, 3’ tentacular nerves; 4, 4’ ten-
tacular ganglia; 5 optic nerve; 6 eye; 7 muscles to the
mouth; 8 nerves to mouth.
302 NEW YORK STATE MUSEUM

Fic.
4 An enlargement of the ganglion of the ocular tentacles,

optic nerve and eye, x 12.

5 An enlargement of the nerve and ganglion of the olfactory
tentacle, x 12.

6 Cryptoicus minutissimus, highly magnified.

PLATE 14

Polygyra albolabris dissected and the organs separ-
ated: 1 buccal body; 2 esophagus; 3 crop; 4 stomach; 5 intestine;
6 rectum; 8 anus; 9 superior lobe of digestive gland; 10 inferior
lobe of digestive gland; 17 ducts of digestive gland; 12 salivary
ducts; 13 salivary glands; 14 penis; 15 vagina; 16 receptaculum
seminis; 17 retractor muscle; 18 glandular portion of the vas
deferens; 19 vas deferens; 20 spermatic duct; 21 uterine canal;
22 spermatic duct; 23 albumen gland; 24 hermaphroditic duct;
25 accessory gland of duct, or talon; 26 ovotestes; 27 renal organ
or kidney, the primary ureter along its upper side; 28 secondary
ureter; 29 opening of ureter, or renal duct; 30 ventricle; 31
auricle; 32 pericardiac cavity; 33 pulmonary vein; 34 large blood
vessel connecting with pulmonary rete; 35 pulmonary rete; 36
supra-esophageal ganglia; 37 tentacular nerve; 38 nerves to
mouth and inferior tentacle; 39 superior tentacles; 40 integu-
ment; 41 muscles from buccal body of integument; 42 superior
tentacular muscle; 43 inferior tentacular muscle; 44 retractor
muscles; 45 muscular peritoneum; 46 muscular collar; 47 cephalic
artery; 48 nerve to muscular collar.

PLATE 15
Limax maximus

The same letters apply to the same organ in each figure.
Fic.

1 The dorsal part of the integument is cut and turned back,
showing the various organs in position.

2 The pulmonary chamber, heart, ete. are turned back, show-
ing the under side of the organs, and the parts concealeq
by them in figure 1.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 303

Fic.
3 The organs are separated, and each organ is shown more

distinctly. i buccal body; 2 salivary ducts; 3 salivary
glands; 4 crop; 5 intestines; 6 rectum; 7 stomach; 8
digestive gland; 9 penis; 10 retractor muscle of the
penis; 11 receptaculum seminis; 12 uterine canal; 12’
spermatic duct; 12” albumen gland; 13 hermaphroditic
duct; 14 ovotestes; 15 nerves to the basal part of the
body; 16 large veins in the integument of the sides of
the animal; 17 ventricle; 17’ auricle; 18 kidney; 19 duct
of kidney; 20 pulmonary veins; 21 respiratory orifice;
22 insertion of retractor muscles; 23 tentacular muscles;
24 mantle; 25 integument; 26 arteries.

PLATE 16
Fia.
1 The under side of the head, showing the mouth; 7 anterior

or upper lip; 2 lateral lips; 3 four corrugations of the in-
tegument surrounding the mouth; 5 triangular ap-
pendages.

2 View from above, the integument and dorsal part of the
basal body cut open and turned back: 7 corrugations of
the integument surrounding the mouth; 2 lateral lips;
38 buccal body; 4 jaw; 5 radula; 6 esophagus; 7 salivary
ducts; 8 muscles of ocular tentacle; 9 muscles proceed-

_ ing from the anterobasal part of the animal, and in-
serted in the olfactory tentacular muscle; 10 muscle pro-
ceeding from the anterobasal part of the animal to the
mouth; 11 muscles of the olfactory tentacles; 12 muscles
from integument to anterior part of buccal body; 13
penis.

3 Digestive organs, etc.: 1 buccal body; 2 esophagus; 3
salivary ducts; 4 salivary glands; 5 crop; 6 stomach; 7
intestine; 8 rectum; 9 anus; 10 arteries, x 3.

4 Enlargement of the under side of the upper salivary gland.

5 Dorsal view of an adult individual.
304

Fic.

NEW YORK STATE MUSEUM

6 Transverse section of a specimen: 1 mantle; 2 envelop of

the shell; 3 shell; 4, 5 pulmonary veins; 6 pulmonary
cavity; 7 mucous part of the integument; 8 muscular
substratum of integument; 9 muscular peritoneum; 10
muscular and mucous basal integument; 11 visceral

cavity.

PLATE 17
Generative organs

genital opening; 2 penis; 3 vas deferens; 4 spermatic
duct; 5 retractor muscle of the penis; 6 receptaculum
seminis; 7 free oviduct; 8 uterine canal; 9 albumen
gland; 10 hermaphroditic duct; 11 ovotestes.

2 Penis retracted, x 3.

3 Penis exserted, x 3.

4 Ovotestes, x 4.

5 Ceca of the ovotestes, enlarged.

6 A still farther enlargement of the ceca.

7 A transverse section of the penis and vas deferens, x 6.

Fic.

11

PLATE 18
Circulatory system, x 3

aorta as it leaves the ventricle; 2 anterior aorta;
3 arteries to the crop; 4 arteries to the uterine canal;
3” arteries to the stomach, intestine and digestive gland;
5 artery to the lower salivary gland; 6 artery to
upper salivary gland; 7 posterior aorta; 8 arteries to the
intestine; 9 arteries to the digestive gland; 10 artery to
ovotestes; 11 artery to penis; 12 artery to vagina and
receptaculum seminis; 13 artery to buccal body; 14
artery to commissural cords; 15 arteries to tentacles;
16 artery to basal part of the body.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 305

Fic.
2-3 Large lateral veins situated in the integument on each side

of the body. Only the larger veins are shown, but they
are connected with the arteries by a fine network of
veins and capillaries, x 3.

4 Showing the arteries and veins of the large lobe of the
digestive gland, x 3.

5 1 pedal sinus; 2 lateral veins.

PLATE 19

Muscular system, x 4
Fia.

1 1 origin of retractor muscles; 2 principal muscular bands;
8 retractor muscles of the ocular tentacles; 4 retractor
muscles of the olfactory tentacles; 5 retractor muscles of
the buccal body; 6 muscles proceeding from the olfac-
tory tentacular muscles to the mouth; 7 muscles pro-
ceeding from the anterobasal part of the animal to the
mouth; 8 muscles proceeding from the anterolateral part
to the olfactory tentacular muscles; 9 muscles proceed-
ing from the anterolateral parts of the animal to the
mouth; 10 muscles proceeding from the anterobasal part
to the olfactory tentacular muscles; 11 muscular fibers
from the buccal body to the mouth.

2 Pulmonary veins, x 4.

3 Under side of the pulmonary cavity, x 4: 1 auricle; 2 ven-
tricle; 3 pulmonary veins; 4 respiratory orifice; 5 kidney;
6 duct or secondary ureter of kidney; 7 anus.

PLATE 20

Muscular system, x 6
FIG.

1 1 buccal body; 2 muscular sheath of ganglia; 3 muscles of
the ocular tentacles; 4 muscles of olfactory tentacles; 5
muscles arising in the basal part of the animal and
connecting with the olfactory tentacular muscles; 6
muscles arising in the olfactory tentacular muscles and
connecting with the mouth; 7 muscle arising in the
basal part of the animal, beneath the ocular tentacular
306 NEW YORK STATE MUSEUM

Fic.
muscles and connecting with the mouth; 8 muscles aris-

ing in the anterobasal part and connecting with the
muscles of the olfactory tentacles; 9 muscles arising in
the anterobasal part and connecting with the mouth; 11
muscular fibers from the buccal body to the lips; 12
muscles of the buccal body; 13 esophagus; 14 salivary
ducts.

2 Buccal body turned back to show the muscles beneath:
1 broad oblique bands of muscles arising in the antero-
basal part and inserted in the extreme anterior part of
the animal; 2 ocular tentacular muscles; 3 olfactory ten-
tacular muscles; 4 muscles arising in the anterobasal
part of the animal, and inserted in the ocular tentacular
muscles; 5 muscles arising on the under side of the
buccal body and inserted in the lips; 6 oblique muscles
of the under side of the buccal body; 7 retractor mus-
cles of the buccal body; 8 retractor muscles; 9 pedal
sinus and bordering veins.

PLATE 21
The numbering of the horizontal lines corresponds to that of the figures.

The same lettering refers to the same organ in all the figures.

Transverse sections of Limax maximus, x 3.

An outline showing the position of the sections.

The section, figure 1, was made at the place designated by
line 1, and so on to figure 12.

0 salivary ducts; 0’ salivary glands; 1 mantle; 2 shell
cavity; 3 shell; 4 kidney; 5 heart; 6 penis; 7 arteries; 8
receptaculum seminis; 9 uterine canal, spermatic duct
and albumen gland; 10 crop; 10’ intestine; 10” eso-
phagus; 11 rectum near anus; 12 pulmonary vein; 13
respiratory orifice; 14 pedal sinus; 15 large lateral veins;
16 smaller lateral veins; 17 veins contiguous to and
parallel with the pedal sinus; 18 digestive gland; 19
hermaphroditie duct; 20 ovotestes; 27 ocular tentacular
muscles; 22 cartilaginous cushion supporting radula;
22” radula.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 307

PLATE 22
Nervous system

1 supra-esophageal ganglia; 2 infra-esophageal ganglia; 2”
commissural cords connecting the supra- and infra-esophageal
ganglia; 3 buccal ganglia; 3’ commissural cords connecting the
cephalic or supra-esophageal and the buccal ganglia; 3” commis-
sural cord uniting the buccal ganglia; 4 stomachic ganglia;
5 nerves to the ocular tentacles; 6 nerves to the olfactory ten-
tacles; 7 nerves to the mouth; 7’ nerves to the lips and adjacent
integument; 8 nerves to the integument of the integument of the
ocular tentacles; 9 nerves to the anterior part of the buccal body;
10, 11 nerves to the posterior part of the buccal body; 12 large
nerves running to the posterobasal part of the animal; 13, 13’
branches of the preceding; 14, 15 nerves from the pedal ganglia
to the basal part of the body; 16-19 nerves from the pedal ganglia
to the sides of the body; 20 cord connecting pedal and stomachic
ganglia; 21 nerve to retractor muscles; 22 nerve to pulmonary
cavity.

PLATE 23

Fic.
1 A profile view of a small specimen of Limax maxi-

mus: 1 respiratory orifice; 2 genital orifice.
2 The radula, profile view, x 6.
38 The same, as seen from above, x 6.
4 The jaw and its retractor muscle, x 6.

5 Dorsal view of upper salivary gland, x 3: 1 salivary duet;
2 arteries; 3 nerves; 4 artery to the stomach.

6 Lower salivary gland: 1 salivary duct; 2, 3 arteries; 4
nerve, x 3.

7 The digestive gland detached from the intestine, etc. dorsal
view, x 3.

8 The same as seen from below; the points a@ are in apposition
when the gland is in its natural position: Z herma-
phroditic duct; 2 arteries.
3808 NEW YORK STATE MUSEUM

Fic.

9 Polygyra albolabris, showing the generative
organs in situ: 7 genital opening; 2 penis; 3 vagina; 4
vas deferens ; 5 spermatic duct ; 6 uterine canal ; 7 talon ;
8 albumen gland; 9 hermaphroditic duct ; 10 ovotestes ;
11 salivary gland; 12 stomach; 13 rectum; 14 beginning
of rectractor muscles; 15 buccal body; 16 tentacular
muscles.

PLATE 24
Fic.
1 A group of eggs, natural size.

2-5 Various forms of eggs, x 4.

6,7 Transverse sections of round and oval eggs.
8 The germinative vesicle, x 48.
9 The under side of the germinative vesicle at the beginning
of segmentation, x 48.

10,11 The ovum during segmentation as seen from above, x 48.
12 A side view of the same, x 48.

18 The segmented mass as seen from below, showing blasto-
pore, endoderm and ectoderm, x 48.

14 A vertical section of the same, showing J the blastopore;
2 the archenteron; 3 cleavage cavity; 4 ectoderm; 5 endo-
derm.

15 Cells. The dark cells are from the ectoderm; the light
from the endoderm, x 250.

16 Showing the endodermal cell mass surrounded by a trans-
parent sac or wall, x 32.

17 Showing the early stages of the formation of the foot and
shell sac, x 32.

18 A stage slightly more advanced, showing the beginning
of the tentacles and shell, x 32.

19 A stage still more advanced showing the beginning of the
podocyst at the extremity of the foot, x 32.

20 A view of the same, from below, showing the podocyst and
the mouth of the animal, x 32.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 309

PLATE 25

This plate shows the gradual development of the embryo from the ger-

minative vesicle.

The germinative vesicle within the egg, natural size and x 8.
Germinative vesicle, x 16.

Under side of same at the commencement of segmentation,
x 16.

The segmented ovum, x 16.

The endodermal cell mass, inclosed by a transparent sac or
wall of ectoderm, x 16.

Showing the transparent sac greatly developed on one side
of the cell mass, x 16.

The beginning of the development of the body form, as
shown by a slight elevation from the cell mass, x 16.

8 A stage slightly more advanced, x 16.

9 The elevation is divided into two lobes, representing the

10
11

12, 13

14
15

16-19

18

20, 21

body proper and the shell sac, x 16.

The embryo within the egg, natural size and x 8.

A stage more advanced than in figure 9. The podocyst is
here plainly shown, x 16.

Still more advanced stages, x 16.

An embryo within the egg, x 8.

In this stage the tentacles are rapidly developing, the body
and podocyst are distinct, and the development of the
buccal body and alimentary canal has begun, x 16.

Gradual development of the embryo. In figure 16 the en-
dodermal cell mass has reached its greatest size, gradu-
ally becoming absorbed in succeeding stages, x 16.

The embryo within the egg, showing the same stage as in
figure 19, x 8.

Ventral and profile views of the embryo within the egg,

x 8; showing a stage more advanced than that repre-
sented by figure 19.
310 NEW YORK STATE MUSEUM

PLATE 26
Fic.

1 Showing the same stage as represented by figures, 20, 21 in
plate 25. The podocyst in this stage reaches its greatest
size, and in the succeeding stages rapidly diminishes in
size, x 14.

2 Ventral view of an embryo of the same stage as repre-
sented in figure 1; showing the base of foot, tentacles,
mouth, lateral lips and corrugations surrounding the
mouth, x 25.

3 A profile view of the same, showing the tentacles and the
“primitive kidney” on the side of the endodermal mass,
x 380.

4 A more advanced stage, x 14.

5 A still more advanced stage. The tentacles have begun to
assume their adult form; the internal organs are assum-
ing definite form; and the endodermal mass and podocyst
are greatly reduced in size by absorption, x 14.

PLATE 27
Fic.

1 Showing the position of the embryo within the egg just be-
fore emerging, x 8.

2 The same removed from the egg, x 16.

3 A fully developed specimen. The integument is cut along
the dorsal line and drawn back, so as to show the internal
organs. See plate 15 for a description of the various or-
gans.

4 An egg containing two embryos, x 8.

5 An egg containing four embryos, x 8.

6 The tentacles and protruded mouth of an embryo; wt su-
perior tentacle; J¢ lower tentacle; tm buccal mass; dp jaw;
m retractor muscle of jaw, x 10.

7-9 Abnormal eggs. These are of frequent occurrence, x 4.
POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 3ll

PLATE 28
Fia.

1 A group of cells after segmentation, greatly enlarged.

2 A group of cells at a later stage; the larger and smaller cells
grouped in polygonal masses, and. distorted from mutual
pressure, greatly enlarged.

3 The cells liberated from one of the polygonal masses, show-
ing their true form, greatly enlarged.

4 The primitive kidney showing the cells and their calcareous
concretions, greatly enlarged.

5,6 Groups of cells from the position indicated by the lettering
5 and 6, figure 5, plate 26, greatly enlarged. The latter
containing calcareous concretions as in the “primitive
kidney.”

7-13 Showing the gradual development of the shell, x 30.

14 The fully formed shell, dorsal view, x 2. The under side of
the shell has very much the appearance represented in
figure 18.
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4
The superior figures tell the exact place on the page in ninths; e. g. 262°
means page 262, beginning in the third ninth of the page, i. e. about one

third of the way down.

Albumen gland of Polygyra al-
bolabris, 257°-58°; of Limax maxi-
mus, 280°.

Apparatus necessary for study,
241?,

Arteries of Polygyra albolabris,
264°-66'; of Limax maximus, 280°-
82°,

Auditory organs, 275°-76'.

Blood of Polygyra albolabris, 267°-
68°,

Carnivorous habits of Polygyra
albolabris, 2477-497,

Circulatory system, of Polygyra al-
bolabris, 262°-68°; of Limax max-
imus, 280'-837.

Cryptoicus, 256’, 2617.

Digestive system, of Polygyra al-
bolabris, 249°-54'; of Limax max-
imus, 278?-79%. :

Direction, sense of, 276°-771.

Dissection, methods, 2427-43,

Eggs of Limax maximus, time of
laying, 293*-94°.

Embryology of Limax maximus,
2907-938.

Entozoa, description of a new
species, 261*-62?.

External features of Polygyra al-
bolabris, 245°-46°,

 

Food of Polygyra albolabris, 2477-
49".

of Polygyra
of Limax

Generative system,
albolabris, 255'-61';
maximus, 2794-80*.

Growth of Limax maximus, rate of,
294°,

Habits, of Polygyra albolabris,
243°; of Limax maximus, 244',

Hancock, Albany, quoted, 275°.

Hearing, sense of, 275°-76'.

Heart, of Polygyra albolabris, 264°;
of Limax maximus, 280°,

Kidney of Limax maximus, 283°
Killing and manipulating, methods,
241-435,

Leidy, Joseph, description of a new
species of Entozoa, 261!-62?; opin-
ion on olfactory organs, 274".

Limax maximus, 2777-949; circula-
tory system, 280'-83'; digestive
system, 278’-79*: time of laying
eggs, 293*-94°; embryology, 290'-
93°; generative system, 279'-80';
rate of growth, 294°; habits, 244°;
muscular system, 2877-89"; ner-
vous system, 283°-87'; explanation
of plates, 309-22,

Manipulating, methods, 241°-43°,

Methods and apparatus, 241’; of
killing and manipulating, 241%-43°.

Microscope, laboratory dissecting,
2414,
314

Movement of Polygyra albolabris,
247°.

Muscular system of Limax maxi-
mus, 2877-899,

Nervous system, of Polygyra albola-
bris, 268°-72?; of Limax maximus,
2838-877.

Olfactory organs, 273?-75°.

Oviduct of Polygyra albolabris,
258°-61',

Ovotestis, of Polygyra albolabris,
256°-57'; of Limax maximus,
279°, 280°,

Pedal gland of Polygyra albolabris,
254,

Polygyra albolabris, 244?-77'; car-
nivorous habits, 2477-49"; circula-
tory system, 262°-68°; digestive
system, 249°-54'; external feat-
ures, 245°-46°; food, 2477-49";
generative system, 255'-61'; ha-
bits, 243°; movement, 247’; nerv-

 

NEW YORK STATE MUSEUM

ous system, 268°-72'; pedal gland,
2547; explanation of plates, 295-
808; shell, 2447-45".

Pulmonary cavity of Limax maxi-
mus, 282°.

Salivary glands of Limax maxi-
mus, 279%.

Sense, special organs, 272*-77'.

Shell of Polygyra albolabris, 244’-
457.

Sight, sense of, 2727-73°,

Smell,-sense of, 273?-75°.

Sochaczewer, ——, opinion on ol-
factory organs, 274}.

Taste, sense of, 272°.
Touch, sense of, 272'.

Uterine canal, of Polygyra albola-
bris, 258’; of Limax maximus,
2807.

Veins, of Polygyra albolabris, 266°;
of Limax maximus, 282°-83°
)

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