Oil- " A- BOUGHT WITH THE INCOME FROM THE SAGE ENDOWMENT FUND THE GIFT OF Henrg W. Sage 1S91 in/lk ^^y/Jloi. U. S. COMMISSION OF FISH AND FISHERIES, GEORaE M.' BOWERS, Commissioner. THE SKELETON OF THE BLACK BASS. BY , Dr. K. W. SHILJKELDT, Extracted from U. S. Fish Commission Bnlletia fur 1899, Fa/ges 311 to 320. Plate 44, WASHmaTOK: GOVERNMENT PRINTING OFFICE. 1900. Cornell University Library QL 638 .C3S38 Skeleton of the black bass. 3 1924 024 782 439 1^2 a ^«^ Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924024782439 U. S. COMMISSION OF FISH AND FISHERIES, GEORGE M. BOWERS, Commissioner. THE SKELETON OF THE BLACK BASS. BY Dr. R. W. SHUKELDX. ,;j:»;f Extracted from U. S, Fish Commission Bnlletiu for 1899. Pages 311 to 320. Plate 44. WASHINGTON: GOVERNMENT PRINTING OPPIOE. 1900. hj^^\^L Bull. U, S. F, C. 1899 (Toface page 311.) Plate 44. UJ ■^ THE SKELETON OF THE BLACK BASS. By Dr. R. W. SHUFELDT. Upward of twenty years ago a special interest was taken by me in the osteology of the large-mouth black bass {Micropterus salmoides) from having discovered in the skeletons of one or two specimens of that species a pair of free ribs articulating with the base of the skull or occiput. As this peculiar anatomical character had never been noted by me before in any of the true bony fishes (Teleostei), it was at the time deemed worthy of scientific record, and so, under the title of "Osteology of the large- mouthed black bass (Micropterus salmoides),^' there was printed in Science, of Cam- bridge, Mass., May 2, 1884, a brief account of this interesting point in the skeleton of Micropterus. It was there stated that this peculiarity "consists in a pair of freely articulated ribs at the base of the occiput. Their heads are received in a shallow facet on either side situated just above and rather internal to the foramen for the vagus nerve. Immediately below each rib occurs the projection of bone that bears upon its entire posterior aspect one of the pair of articular condyles for the first free vertebra of the spinal column. Still beneath these condyles is seen the conically concave facet for articulation, with a similarly formed surface occurring on the centrum of the vertebra just mentioned, and the one which I believe would be described as the atlas." This pair of ribs is directly in sequence with the abdominal ribs on either side. Their occurrence in this situation might be accounted for by saying that several of the anterior vertebrae of the column had been absorbed by the occipital elements. Mr. Bridge found such a condition in Amia, though no free ribs were present [Journ. Anat. and Phys., xi, 611, London, 1877). In further commenting upon this it was added that "in the cranium of Micropterus, however, I should think that this would be highly improbable. Both the first and second vertebra of the spinal column of this bass support each a pair of free ribs, and a mid-series of the other abdominal ribs bears epipleural appendages. Dr. Gunther states, in his account of the osteology of the Teleostei, in the article ' Ichthyology' of the Encyclopaedia Britannica (vol. xn,9thed.), that 'the centrum of the first vertebra or atlas isvery short, with the apophyses scarcely indicated. Neither the first nor the second vertebra has ribs.' I have a yellow perch [Perca flavescens) in my possession where both of these vertebrae support a pair of free ribs." In conclusion, I added that " should an examination of the young of the black bass show that none of the anterior vertebrae of the column were included with the occipital segments, but that these ribs are truly occipital ribs, then they become of interest from several points of view." This discovery was made in March, 1884, and, as has been noted above, was published the following May, and attracted the attention of no less a distinguished 311 312' BULLETIN OF THE UNITED STATES FISH COMMISSION. authority than Mr. McMurrich, who at ouce noticed it in the same periodical (Science, No. 69, 1884), but his remarks possessed upon this point but little value, inasmuch as he had not taken the trouble to examine a specimen before printing them, and therefore had no material before him when he wrote. Nevertheless they were replied to by me in another contribution to Science (vol. iii, No. 72, June 20, 1884) under the title of "Osteology of Micropterus salmoides," and this time a figure of the left lateral view of the cranium of this species of fish was published that showed the pair of free ribs on the occiput. Moreover, in this communication the literature of the subject was reviewed, greater detail added in regard to these fve&occipital ribs, pointing out that Mr. McMurrich was entirely wrong in his conceptions of their morphology, and that "Dr.'Sagemehl, in his valuable paper on the cranium of Amia [Morphologisclies JahrbucH, ix), is very explicit in what he says about the coossification of the three vertebrae with the basi- occipital of this ganoid ; and if this author had been aware of such a state of affairs as I here figure in any of the Teleostei, he certainly would have brought it forward in connection with op^o :bo. Y\G. 1, — Left lateral view of cranium (if M. salmoides, showing a pair of ribs at the occiput; life size from nature, by tlio author, from his own disdectioua. ^S. effi., supraetbmoid; J^r., frontal; Si]., squamosal; Pa., parietal (not well in sight) ; Up. O., cpiotic; S. O., supraoccipital; Ft, O., pterotic; oc. r., occipital ribs; vg.t foramen for vagus nerve; E. 0., oxoccipital; B. O., basi-occipital ; Op. O., opisthotic; Pr. O., prootic; P(/.,po8tfrontal; As., alisphenoid; Bs., basisphenoid ; Fr.S., paraspheuold ; Pv/., prefrontal; To., vomer. tlie discussion of that subject. They are two very significant facts, that these ribs in Micropterus articulate beyond the vagus foramen and that they are apparently con- stant. I have since found similar structures in a specimen of Orcynvs thynnus, and rather suspect it in the Scombridce.^' The figure that illustrated this letter to Science reappeared in my memoir entitled '• Outlines for a Museum of Anatomy," which was published by the Bureau of Education at Washington, D. C. (Department of the Interior, 1885, p. 60, fig. 6). This figure is introduced in the present memoir as fig. 1, as it illustrates a very important part of the skeleton of the black bass. Beyond giving this cut, however, there was nothing especially added to our knowledge of the osteology of this bass in my " Outlines for a Museum of Anatomy," further observations being reserved until my more extensive memoir was published by the U. S. Commission of Fish and Fisheries, in 1885, entitled "The Osteology of Amia calva, including certain special references to the skeleton of Teleosteans." In this work very considerable reference was made to the skeleton of Micropterus salmoides, and six figures were given in the plates illustrating it. Nevertheless the THE SKELETON OF THE BLACK BASS. 313 paper as a whole was devoted to the osteology of Amia, aud what I had to say there about that of the black bass was only by way of comparison. While I shall take advantage of those previous researches, the present memoir is piimarily intended to give an account of the skeleton of this well-known bass in its entirety, and, as will be observed, a full-page plate is likewise here given which presents a side view of the entire skeleton of the small-mouthed black bass {j\Iicropterus dolomieu). This is from a photograph made from a specimen prepared by Dr. Jacob L. Wortmau. Fig. 27 of my Amia paper gives a left lateral view of the skull of Micropterus salmoides, natural size, being reproduced from a drawing made by me from my own dissections. This ligui-e is here reproduced as lig. 2 of the present memoir There is also given in ^FH.T. .- r^,/<,.r. 'Fia. 2.— Left lateral view of stnll of 21. salmoides, with the skeleton of other parts connocted with it posteriorly. Natural size and drawn from the actual specimen hy the author from liia own dissections, lettering the same a.s in fig. 3 and other figuics of Ihc memoir. fig. 3 of the text the right lateral view of the skull of the small-mouthed black bass, a drawing made from my own dissecti(ms and not before used in any ichthyological paper. This cut will prove especially useful, inasmuch as the skull from which it was drawn is the same as that in the complete skeleton of the sinall-mouthed black bass in plate 44. In no other class of backboned animals is the slcnll so large in proportion to the skel- eton of the trunk or body as it is in fishes, and to this statement the black bass offers no exception. The study of the skull in osseous fishes generally was for a long time considered, even by anatomists, one of themostdifQcultof nil problems in biology, and even at the present time it is by no means an easy task. During the last ten or fifteen years, however, owing to the numerous text-books and various irianunls devoted to the elements of anatomical science, this subject has been very much simplified. 314 BULLETIN OF THE UNITED STATES FISH COMMISSION. The late Sir Eichard Owen, in his celebrated work on "The Anatomy and Physiology of Vertebrates," said : It may well be conceived, then, that more bones enter into the formation of the skull in fishes than in any other animals; and the composition of this skull has been rightly deemed the most difficult problem' in comparative anatomy. "It is truly remarkable," writes the gifted Oken, to whom we owe the first clue to its solution, " what it costs to solve any one problem in philosophical anatomy. Without knowing the what, the how, and the why, one may stand, not for hours or days, but weeks, before a fish's skull, and our contemplation will be little more than a vacant stare at its abmplex stalactitic form." kow, from this it will be easily appreciated that to write the " what," the " how," and the " why" of the entire skeleton of Micropterm would simply make a volume of several hundred pages, an achievement by no means contemplated when this brief S'ytnt Fig. 3 — Eight lateral view of skull of M. dolotnieu, witL other bonea; natural size, by the author. Pma:, premaxillary; PZ., palatine; na., nasal; ^t/i., ethmoid ; Pr/, prefrontal ; j4fi., alisphenoid; Pr., frontal; Ptf., poatfrontal; Sq,, squamosal; Pa., parietal; Ft o., pterotic; S. O., supra- occipital; s. I., supralinear; lUp. o, epiotic; Ic, interneural spines; La., lacrymal; Pr.s., para- sphenoid; S.or., suborbital; Pr.o., prootic; i?s. basisphenoid ; (?. Z7i/.. glossohyal; D.,dentary; Ar(., articular; jlfa;., maxillary; a, admaxillary; i?w^(., entopterygoid; Eept., ectopterygoid ; M. PL, metapterygoid; P&t. T., posttemporal ; Pr. S., proscapula-; Pf., pectoral fin; Hyo. C, hypocoracoid ; O^., operculum; 5^. O^., suboperculum; jLjigr., angtitar; ^i/7n., symplectic; n.8., neural spine; Psto. T., posterotemporal ; T., teleotemporal ; T'., lower teleotemporal ; Bs.P., branchiostegal rays; P. Op., preoperculum ; I. 0^., interoperculiim; H. M., hyomandibular; ()w., quadrate ; r.,rib; Aaf., actinosts ; JETj/p. O., hyporcoracoid. memoir was undertaken. Its aim, in fact, simply consists in bringing together what I have already printed about the skeleton of this well-known and widely distributed American fish, and arranging that subject-matter in condensed monographic form, adding to it anything that may not have been touched upon in previous publications. The paper will fulfill its mission if it excites au interest anywhere in the study of the skeleton in fishes, and brings before the reader facts which will facilitate such studies, and in a way prove to be of assistance in comprehending future memoirs upon the osteology of fishes. The best method of studying the bones composing the slcull and appendages in any adult specimen of an osseous fish, apart from comparing those bones with the corre- sponding or analogous ones in the skull of any other animal, is to secure several perfect heads of the fish to be thus considered, as near as possible of the same size, and pre- THE SKELETON OF THE BLACK BASS. 315 pare them in the following manner: One head is to be macerated in warm water until all the soft parts can be removed and the bones separate from each other, except those in the cranium. Each boue should be removed by itself, laid out to dry in a relative position it occupied in the skull, and identified if possible. For this latter operation the second skull is intended, and this one should also be partially macerated, but only so far as to moderately soften the tissues; then by the most careful dissection, all of these should be removed, and the entire osseous structure of the head left precisely as it is in life, in so far as the bones are concerned, the latter beiug held together only by their ligaments. This prepared skull is then properly dried. The third head, prepared exactly like the second, is longitudinally sawed in two by means of a very line saw, passing to one side of the crest of the supraoccipital. By means of these two halves we are enabled to study the osseous parts of the interior of the brain case and the bones at the anterior extremity of the skull. Fig. 3 of the present paper, as well as the illustration of the skull of the large- mouthed black bass in fig. 2, will give an idea as to how the bones are normally related to each other, and as shown in the heads of the two species of Micropterus jirepared by the second method. Fig, 21 of my memoir on Amia calva shows the head, or rather the cranium, of a yellow perch {Perca fiavescens) longitudinally bisected in order to bring into view the bones in the brain case. As has beeu stated, if the head of this bass is allowed to macerate in water for a sufficient length ot time all the more loosely attached bones, including .the occipital nbs (fig. 1, oc. r.), will come away and separate from each other. This leaves the cranium all in one solid piece as shown in fig. 1. This, as has likewise been said, is composed of its own bony cranial segments, which require more protracted maceration to sepa- rate them.. This cranium, and many fish possess one a good deal like it, is of a pyramidal form, the base being formed by the occiput and the apex by the vomer («o), which is here produced downwards as a j)rominent beak, being rounded in front, and thickly studded with fine teeth upon its inferior surface. A very noticeable feature of the cranium are the orbits. These are large and in no way separated from each other by an osseous medio-longitudinal plane standing between them. Above, they have a wide, arched roof, concave from before, back- wards; while below there is but the median rod, composed principally of the vomer (ro.) and the parasphenoid (Pr. 8.). Other bones entering into the bounding walls of the orbits are the frontals above [Fr.), the prefrontals anteriorly (Pr/.),the alisphenoids {As.), and the postfrontal {Ptf.). On top of the cranium, behind, and occupying its hinder half, there are five conspicuous crests, a median one and two lateral ones on each side. These are well shown in fig. 1, and have been fully described in my Amia memoir. They vary greatly in the crania of different species of fishes, being entirely absent in some species and very prominent in others. In the common cod (Gadus), for example, the median crest is thick, strong, and high, and produced far backwards and to the front to a point over the center of the orbits. Again, in the black sea-bass {Gentropristes striatus), of which I have prepared one or two perfect skeletons, these crests are more as in Micropterus, but by no means exactly the same, as these two species belong to very distinct families. At the back of the cranium there are to be noticed chiefly the circular, conically concave facet for the atlas vertebra, with above it, one upon either side, the pair of zygapophysial facets for the corresponding ones on the same vertebra. These have above them 316 4 BULLETIN OF THE UNITED STATES FISH COMMISSION. FiQ. 4. — Left lateral view of mandible of M. salmoides. Natural size, b}- the author, from hia own dissections, tho various bones having been pulled apart to show their entire shape. D, dentary; m.u., Meckel's cartilage; -i?-i., articular; Ang. , ansnlar. again, iu the middle line, the somewhat small subcircular foramen magnum, inclined to be subcordate in outline in some specimens. Often iu the common cod, always in old individuals, I believef this first or atlas vertebra fuses with the base of the cranium, ' and its long neural spine runs up nearly to the top of the supraoccipital crest, being in contact with the posterior margin of the same for the entire way. Apart from the cranium the chief features of the skull consist in the jaws, the upper one being formed by the maxillary {Mx.) on either side, and the prasmaxillary and its fellow in front bearing the teeth (Pma;,) (fig. 3). These structures have been fully described in the Amia memoir, and the two figures there devoted to them are here reproduced as figs. 3 and I. Attention is also invited to fig. 5, for that, talceii in connec- tion with fig. 3 of the present paper, will clearly show the relations of another group of bones of the skull, namely, the opercular bones, or those of the gill-covers {Op., P. Op., S. Op., and I. Op.). Considerable attention has already been paid to these in the Amia contribution. In connection with them will be found the symplectic, a very interesting element in many bony fishes (fig. 3, Sym.). Then there are the bones of the suspensorium, connecting the cranium with the lower mandible (H. M., Sym., and Qu.). Of these, through the in- tervention of the interhyal, the hyomandi- bular arch has also suspended from its lower extremity the hyoid arch, while its upper and posterior extremity also articulates with the operculum. Again, in the pterygopalatine arch of this bass we meet with the metapterygoid, the ento, and ectopterygoid and the palatine, and the relation of these bones to each other are shown in fig. 3 of the present paper and described in my Amia memoir, where also the hyoid and branchial arches of Micropterus have been touched upon in considerable detail. In this connection I have pointed out that the branchiostegal rays (fig. 3, Bs. B.) constitute the skeleton of an organ of defense to the respiratory apparatus, and that many believe that the opercular bones are merely modified branchiostegal rays. Passing from the skull and its arches we come to consider the shoulder girdle, a sequence of bones that have been differently viewed and differently named by different ichthyologists. In my work upon Amia calva I have contrasted in tables these various opinions and appellations, and figured the bones, and also named a bone, the supra- linear (si.), that is in a way connected with the shoulder girdle above (see fig. 3). Fig. 5. — The left outer aspect of the upper jaw of M. saltrKyides, together with the hones associated with it. These latter are slightly dislodged from their normal positions, the better to show their relations. About two-thirds natural size, from the actual specimen, by the author, from his own dissections. Mx, maxillary; Ptnx, premaxillary; I'L, palatine; a, admaxillary. THE SKELETON OF THE BLACK BASS. 317 In the latter, in Micropterus, we bave a posttemporal {Pst. T.), a posterotemporal {Psto. T.), a teleotemporal (T.), a lower teleotemporal (T'.), a hypocoracoid {Hyo. c), a hypercoracoid (Hyp. c), and a proscapula (P. 8c.). Now the Mteral or the pectoral fins in this bass are connected with the shoulder girdle through the intervention of four little bones, called actinosts (flg. 7, Ast.); they are very small, graded in size, and are formed somewhat like little hour-glasses or dice-boxes, being enlarged at their articular ends and constricted at the middle. Anteriorly these actinosts articulate with the posterior border of the conjoined hyper- and hypo-cor:icoids, while poste- riorly they aflbrd support and attachment for the bony rays of the pectoral fin (P/.). In the several specimens of black bass 1 have dissected and others I have examined. Fig. 6. — Inner aspect of opercular bones, hyoid. syraplectic, and other elements of M. salmoides. Left side, natural size, by the author, from his own dissections. Op-, operculum; S. Op., sub- opercnlum; JPr. Op., preoperculura ; I. Op., interoperculum ; M. J/., liyomandibular; M. PL, metapterygoid ;