¥) s ed bia! Fis ors iwi rebar go Pere Pee PGS Seana bsceielie ae ree Pr Aa a Six: ralatota ata. SS PIT i SOND eee haart SE Ss Aen . Z or srriract cAphch sean Se a ee 4 as Are: } See tte SS SANS. : Pet SES - a R Siete see eres ete) ~~ Som Seren Site So “ee 7 > : - es - . = ea », J &200gh Ars 4 > eg: ma. ey So TRANSACTIONS Chee .] & y bene ste Cte shecrtl Sime” OF THE ZOOLOGICAL SOCIETY OF LONDON. Vou. VIII.—Parr 9. LONDON: PRINTED FOR THE SOCIETY : SOLD AT THEIR HOUSE IN HANOVER-SQUARE; AND BY MESSRS. LONGMANS, GREEN, READER, AND DYER, PATERNOSTER-ROW. 1874. Price 42s. Taylor and Francis, Printers,] {Red Lion Court, Fleet Street. PUBLICATIONS OF THE ZOOLOGICAL SOCIETY. PROCEEDINGS OF THE COMMITTEE OF SCIENCE AND CORRE- SPONDENCE OF THE ZOOLOGICAL SOCIETY OF LONDON. ? 8vo. 2 vols. To Fellows. To the Public. Part I. 1830-31. 1 vol. 8vo. Pato) EA ea Pri CelAs a GOA retin cm Ose Sas ABE ates y BONY SCS) eH HO 1 AU ge Sy AS Od eae en inGgs PROCEEDINGS OF THE ZOOLOGICAL SOCIETY OF LONDON. 8vo. 15 vols. and Index. (First Series.) Price to Price to the Price to Price to the Fellows. Public. Fellows. Public. Part I. 1833. 1 vol. 8vo. 4s. 6d. .. 6s. Part IX. 1841.1 vol. 8vo. 4s. 6d. .. 6s. ¥ Il. 1834. a 4s. 6d. ..* 6s. 5 X. 1842. (out of print.) Hi Ill. 1835. a As: (Gd ue OSs HA XI. 1843. 1 vol. 8vo. 4s. 6d. .. 6s. IV. 18386. a 4s. 6d... ‘68. Ae XIT. 1844. a AsNGda Cn Os: “ VY. 1837. a5 As Gases: Pees 2. OW H ta ese tay . As. 6d. 6s ne VI. 1838. * 45N6d5- i.) 6s. Se Ve S46. * As. 6d. 6s VII. 1839. om 4s06d. .. 6s. 3 XY. 1847. 3 4s. 6d. 6s VIII. 1840. x ASM Gas) en OSs Index 1830-47. pe 4s. 6d. 6s PROCEEDINGS OF THE ZOOLOGICAL SOCIETY OF LONDON. 8vo. 13 vols. and Index. (Second Series.) Without Illustrations. With Illustrations. To Fellows. To the Public. To Fellows. To the Public. Sih CO oy ate Part MOV B4 Sis volspSv0: s4ssOGs prc. eae OSsn on une wan For eel siiapatien () Tre Xe) As XVII. 1849. a3 ASUS ene he dGstg et am Ba neha Et) a DS Amal) XVIII. 1850. a ASS 0 sam pase DaNGss Aig expt SAS) 118 0 of XIX. 1851. ASO nist ee OS. Ox L620 A lee 2) x XX. 1852. oS ASAG tami tenn OS: apn pede lay 2 Tae @ ed KXI. 1853. 55 As Go aa te OS: 3 0 18. 0 1.4920 ie XXIT, 1854. 3 ASiGdsiae tae GSs: Aa as lea Oe) mG ee0) PA XONG ei wel Soars ns As: Gaston ee OSs Patel erga 1a Shae) XXIV. 1856. a As Gada eee wanOS: ee ELT aO) eG XXYV. 1857. oe As. Gish vere Mente OSs Ean Cond e910) Te 7h M5 XXVI. 1858. 5 As Gd Gitehelaa Ose eA Be S20) PA D0) XXVII. 1859. i AsiGdaee en we aes, fang wile iD ee) CH Ot Xp) » XXVIII. 1860. i ASNGO Nineteen OS epi tel Dye) (0) Index 1848-60. us As Gauci iekcoes Oe ILLUSTRATIONS TO THE PROCEEDINGS OF THE ZOOLOGICAL SOCIETY OF LONDON. 1848-60. 8vo. 6 vols. To Fellows. To the Public. Ee Wondeets BEN a) Mammealiay err cis Tvole, containing Sp Mblatesiia i). wih. in banc eo) WS r Onur nna lies Mesa an() AVES CsA evan alee 2 vols., ud ele es SNM MICH mame: an RTA OL et Rae kaa (D) Reptilia et Pisces 1 vol., 3 AS tie, Sas HDL areal Osetra OU AC Mollusca) ects eee 1 vol., ue Sle Arn Mpa iran amos. oe co TUN a (Gy Annulosa et Radiata .. 1 vol., ds OO RAS Ane T Opec Soe nO [ Continued on page 3 of Wrapper. | (| Lake Ws Pitta [ 501 ] XVI. Researches upon the Anatomy of the Pinnipedia.—(Part III.) Descriptive Anatomy of the Sea-lion (Otaria jubata). By James Muniz, WD, F.LS., F.GS., &e., late Prosector to the Society. Read December 6th, 1870. [Puates LXXV.-LXXXII.] ConTENTS. I. The Skeleton and Cranial changes, p. 501. V. Hyolaryngeal and Respiratory Organs, p. 546. II. The Nervous System, p. 517. VI. The Digestive System, p. 553. III. Sensery Apparatus, p. 534, VII. Urino-generative Organs, p. 567. IV, The Vascular System, p. 535. VIII. Description of the Plates, p. 573. HAVING in the first part of this Memoir treated of the exterior, of the fleshy body, and of the ligaments knitting the osseous frame of the Sea-lion, it follows that I next take the skeleton into consideration. HH. M. Ducrotay de Blainville, in his magnificent ‘Atlas of Osteography,’ has figured the skeleton of our Otary, and that of the Walrus and the Common Seal; but neither of the two former is placed in the peculiar and distinctive attitude these animals assume on land. For this reason I have refigured that of the Sea-lion, and added separate illustrations of each of the carpal and tarsal bones—a decided want in his great work. The series of crania figured by me I shall refer to en passant. I. THE SKELETON AND CRANIAL CHANGES. 1. The Skull. a. General aspects.—Seen in profile, the skull of the Society's young or nearly adult ¢ specimen of Ofaria jubata exhibits a remarkable flattening of the upper cranial surface; the base of the cranium from this view also appears pretty level, and is nearly parallel with the horizontal plane of the vertex. From the nasals anteriorly the skull slopes considerably ; and posteriorly the occipital truncation is interrupted by the pro- jecting condyle. In old age, as subsequently to be shown, the skull of this species does not retain the above-mentioned features ; but these evidently hold good in a certain stage of growth. Three segments or regions are readily mapped off in this side-view. The first or naso-maxillary one occupies rather less than a third of the entire length of the cranium, and includes the nasal, the intermaxillary, the maxillary bone, and the teeth as far as the fourth premolar. The anterior or inner margin of the orbit bounds this segment VOL. VIII.—PART Ix. June, 1874. 4a 502 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. behind. The second, orbito-frontal or middle region is chiefly formed by the orbit itself. It embraces, moreover, a portion of the vacuity of the temporal fossa, externally is guarded by the malar arch, is bounded above by the frontal bone and supraorbital process, and below and within is defined by the pterygo-palatine wall. Its length is almost an exact third of the long diameter of the cranium. These two anterior segments or provisional boundaries together comprise the facial region, which here bears a proportion to the entire length of the skull as 6 is to 10. The third, hinder and largest segment, the temporo-occipital, is nearly as deep as it is long, and it thus has a marked rectangular configuration. The upper cranial surface exhibits even more definitely the three regions just spoken of. That portion containing the brain is broad, and more particularly so at the exoc- cipitals. The frontals are deeply scooped out opposite the zygomatic arch; and this narrowing contrasts with the prominent postorbital processes. Hach malar areh has an external flattened aspect, and only slightly veers inwards anteriorly. At the maxillary bones the skull is narrower; and quite in front these and the premaxille form an un- evenly rounded muzzle; four bosses (see fig. 1) indicate the relative positions of the outer incisors and canine teeth. b. The Cranial Bones.—Anfractuous low ridges chiefly indicate the occipital elements, which otherwise are more or less coalesced. The basiocciput inferiorly is somewhat oblong in shape, and rather longer from before backwards than across; the foramen magnum is nearly circular in figure. The condyles form, posterior to the opening, an inferior projecting and thickened semilune of bone; but the upper margin of the foramen magnum, composed of the inferior hinder border of the supraoccipital, is thin. A large exoccipital canal’, or condyloid foramen, pierces the bone just within the articulating surface. The supraoccipital forms a well-defined arch, bounded by a broad moderately raised lambdoidal crest. ‘The surface of the supraocciput is very uneven, being marked mesially by a sharp crest, on either side of which are deep hollows for the nuchal muscles. The parietals are narrow, flat-topped, and short; suturally they are firmly connected with each other, and interossified with the squamous portion of the temporals. The squamous element of the temporal bone is broad and flat. The mastoidal surface is rather prominently ridged just behind the external auditory meatus, or with a moderate- sized paramastoid process; rearwards it is sunk flat, and joins a narrow, scarcely appre- ciable paroccipital process. The tympanic bone is fair-sized, but not inflate. It is directed obliquely inwards, backwards, and downwards, ending in a sharp margin; superficially (¢. e. inferiorly) it is broadly grooved and indented on its inner face. A slight ridge is all that indicates a styloid process; but there is a short tooth-like cusp projecting forwards in front of the tympanic, and overlooking the carotid foramen. The glenoideum is narrow antero-posteriorly, but broad transversely, and moderately ‘ A term proposed by Mr. H. N. Turner, see P. Z. 8. 1848, p. 75. DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 503 scooped; the jugal extension is a tapering rod. The jugal bone is not very stout, though at its middle high, in an upward angle. Bifurcate in front, it forms a firm union with the maxillary retrovert process. A considerable part of the face or muzzle is taken up by the intermaxillary, so that, excepting the canine eminence, each maxillary chiefly outflanks the cheeks only. The basal segment of the maxilla rises high, is flatly convex, and of fair breadth. Behind, the canine eminence is deeply and widely grooved, where lie the thick infraorbital nerves and vessels. There is a small but distinct antorbital prominence. The max- illary orbital surface is moderate, and tolerably vertically concave forwards. The pala- ‘tine region of the maxillary is of fair breadth, and terminates in a long spear-shaped palatine strip guarding the palatine plates of the palate-bones almost to the posterior nares. Each premaxilla is flattish and truncate anteriorly towards the alveolus, and rises therefrom in a narrowing outspread arch enclosing the anterior nares. ‘The narial orifice in front is heart-shaped, 12 inch deep and 1} inch at its upper widest part. ‘The upward strip of the premaxilla is inserted between the nasal and maxillary bone as a narrow wedge. The large turbinals are much convoluted and almost occlude the narial passages, but within the maxillary area. The vomer is in great part hidden, and has no connexion with the horizontal palatine plates. The nasals in some respects are like the premaxillaries in being wide below and narrow above. Each is 1:8 inch long, and about half an inch at widest or below. They are suturally connected nearly their whole length, posteriorly divaricating; the forks fit into the frontal. One half of their outer margin abuts against the maxilla, the remainder in front lies upon the premaxilla. The frontal bones are peculiar from their length, postorbital processes, and great constriction behind these. Their upper surface is smooth and flat anteriorly, and widely conyexly arched behind. Their orbital surfaces are of great length, considerably scooped out, and but moderately deep, a long vacuity existing between them and the maxillo- palatines. The palatine plates of the palate-bones, as has been noticed by many authors, are un- commonly long and broad—in this case fully 25 inches in antero-posterior, and above 14 inch in transverse diameter. Their hinder margins are transversely abrupt, and the posterior nares constricted. Laterally and exteriorly the palatine walls reach high, and present a great pterygo-sphenoidal surface. The basisphenoid is short, but wide. ‘The pterygoid processes stout, and with a sharp recurved hamular process. The alisphenoids are fair-sized, distinguished by a square boss where they join the postfrontals. There seems, however, to be a large orbital plate: but this is mainly composed of the postfrontal; for the orbito-sphenoidal area is very narrow and small. c. The Mandible.—The two halves of the inferior maxilla have no bony anchylosis, but are united to each other by synchondrosis. ‘This separation is not merely the result of 4a2 504 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. age; for I find such symphysial cartilaginous union obtains, not only in the adult speci- mens of Otaria jubata, but even in undoubted old animals of the same species. Each body possesses a shallow curve, the concavity of which looks inwards; and the halves together thus form a tongue-shaped arch, ending in front in the broadish deep sym- physis. Immediately beneath the well-marked incisor-fosse and foramina, the edges of the symphysis pout forwards in a low but distinct median mental crest, some half an inch in vertical depth. Below this the rami gradually diverge from each other, inclining downwards and backwards as they each form a thickened posterior symphysial angle. The extreme length of the lower jaw measures 7:25 inches; the greatest diameter (which is at the condyles) is 5°3 inches. A row of foramina as numerous as the molar teeth on the left side, and less by one on the right, occupy a line trending downwards from the alveolus, opposite the last molar, to below the middle of the bone, and anteriorly vertical between the first and second molar teeth. The most anterior of these is the largest, and may represent the mental foramen of Man; but here, in the Sea-lion, the vascular supply is great, and accord- ingly supplied with an increased number of nutritious channels. A narrowing and thinning of the bone distinguishes or separates the body from the ramus; this nearly median contraction has the effect of giving the side of the jaw a somewhat long and irregularly bordered figure-of-eight contour. At this narrowest part, just behind the last molar, there is a breadth or vertical depth of 1:2 inch, and a thickness of 04. From it the ramus commences, and very gradually widens, its thin coronoid lamina rising at an obtuse angle to the body. ‘The angle, a flattened rhombic plate, is inflect, with a deepish emargination in front. The condyloid neck is compressed antero- posteriorly. d. Foramina of Lower Base'.—The anterior palatine are fissures of some magnitude. Marked postpalatine foramina do not obtain; but instead a linear series of minute open- ings reach from opposite each penultimate tooth back to the end of the maxillary splint, in apposition with the lengthened palatal arch. There is an alisphenoid canal per- forating longitudinally the base of the pterygoid, and communicating with the spheno- orbitary region. A Vidian canal, admitting a fine bristle, can be traced along the inside of the pterygoid root. A fair-sized foramen ovale lies behind and outside the alisphe- noid canal; and exterior to it is the postglenoid foramen. Directly posterior to the ovale, and in a somewhat irregular transverse recess, there are close together the lacerum medium, anterior opening of the carotic canal, hiatus Fallopii, and fissura Glasseri—the said recess, moreover, being surmounted posteriorly by the tubercle developed in front of the tympanic. The orifice of the meatus auditorius externus is sunk in a conical hollow between the mastoid eminence and the tympanic bulla, the large stylomastoid foramen being situate close to its rear. Still further back, and more towards the ‘ Compare respectively the interesting researches on this subject in the Carnivora by H. N. Turner, as cited, and Prof. Flower, P. Z. S. 1869, p. 4; also Prof. Owen’s pithy descriptive remarks on specimens in the Hun- I pithy I terian Museum. DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 505 median line, is the very great horseshoe-shaped jugular vacuity. At its fore border, partially hidden within the bone, is the entrance of the carotid canal, which pursues a course through the tympanic, opening, as aforesaid, at the lacerum medium. A shelf of bone divides the postcarotic foramen from the deeper-placed aqueductus cochlee. Lastly, to the rear, and a trifle within the jugular fossa, is the basal opening of the anterior condyloid foramen. e. Interior of the Skull.—As regards peculiarities in the form of this cavity, allusions will be found under the description of the encephalon ; here I confine my remarks to the osseous superficies and foramina. Laterally the walls of the calvarium are exceedingly thin—anteriorly, or in the frontal region, excessively thick and cancellous—occipitally equally porous but very moderate in thickness, and with capacious venous channels. The bony tentorial plate, necessarily broken on removal of the vertex, as displayed in fig. 10, is uneven, and pitted with minute and larger-sized foramina. The anfractuosi- ties of the canopy of the skull, and the irregular cerebral-pitting depressions are most unusually well marked; and, moreover, innumerable minute and larger-sized foramina bear evidence of the great vascularity of the osseous structure. The longitudinal venous groove is very deep and well pronounced ; and so are the furrows lodging the meningeal arteries &c. The floor of the cavity (somewhat bluntly boat-shaped) possesses numerous irregu- larities and vacuities; but the orbito-frontal parietes are smoother and incline to the perpendicular. The olfactory fosse are narrow, high, and deep, the cribriform plates of the ethmoid assuming the vertical, with a retroverted spinous partition. Immediately behind the latter is a single low-arched perforation for the optic nerves, each nerve escaping into the back of the orbit through the orbito-sphenoid bone, the perforation drilling the median wall (fig. 5). Along the solid mid-basilar plane, successively from before backwards, the noteworthy points are:—adjoining the optic arch a transverse cleft, through non-ossification of preesphenoid suture ; a full broadish processus olivarius, comparatively deficient in mid clinoid processes; a deeply excavated sella turcica, whose bayed front margin carries relatively large angular postclinoid processes ; a scooped basi- sphenoid lodging the pons Varolii; to the rear of this, in the basioccipital, a great lop- sided hollow (possibly a vascular recess), chiefly to the left, though shown on the right in the reversed fig. 9. At the sides defined areas correspond to the orbito-parietal and temporal lobes of the cerebrum, whilst that which receives the cerebellum and lateral sinuses is markedly characterized by its depth, prominent nodular periotic, and large jugular orifice. Of other fissures and visible foramina, that agreeing with the lacerum anterius extends half an inch antero-posteriorly, an outer eaved bony plate partly overriding it; a groove about another half inch leads back and outwards to a large foramen ovale, these and an inner adjoining space (in the fresh subject) being occupied by the Casserian ganglion and fifth-nerve divisions. What apparently answers to the lacerum medium (giving ingress to the internal carotid artery) and the foramen spinosum is a widish perforation and 506 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. adjoining minute accessory tiny open fork, situate behind but to the inside of the ovale, and immediately in front of the periotic. The latter nodular bone dominantly projects, a concavity of the cerebellum at the flocculus resting thereon. Anteriorly the aquie- ductus Fallopii is barely visible in this view; neither is the meatus auditorius internus, which looks towards the median line; and the aqueeductus vestibuli similarly occupies a recess on the posterior face. Below the last is the carotid canal, behind the large jugular perforation. An anterior condyloid foramen pierces the corner betwixt basi- and exoccipitals, running nearly vertically towards the jugular groove. For a description of the longitudinal vertical section of the aged skull, viz. that in Pl. LXXVIL. fig. 22, I refer to Prof. Owen’s notice in the Cat. Coll. Surg., specimen No. 3971. It is sufficient for my purpose to call attention to the great occipital crest, thickness of frontal, position of ethmoid and turbinals, maxillo-palatine cleft, and osseous tentorium, as all more fully pronounced in character than what obtains in younger skulls which, nevertheless, in other general respects agree. f. Seaual differences.—In a previous communication to this Society, I directed attention to certain visual distinctions extant between the male and female skulls of Otaria jubata, and gave figures of the same, hereunder reproduced. I was not then aware that Owen had commented on the same fact, and therefore now append his remarks in a footnote '. tise Palatal views of adult male (fig. 1) and female (fig. 2) skulls of Otaria jubata, To scale 3 nat. size. From P.Z.S8. 1869, p. 103. | << Tt differs from that of the male in its inferior size, but agrees with it in all essential or modifiable cha- racters. The more feeble bite and smaller temporal muscles have not required the elevation of the temporal DR. J. MURIE ON THE ANATOMY OF THE SEHA-LION. 507 They apply to the skull figured by me in Pl. LXXVIL. figs. 16,17, which is that numbered 3968, Cat. Coll. Surg. Besides the points here displayed in palatal views, a comparison of the crania in the accompanying Pl. LAXVII. further bears out state- ments concerning said differentiations '. g. Progressive Cranial changes—Although writers previously had incidentally ad- verted to an alteration in the form of the skull with age in some of the Eared Seals, yet no one has so forcibly pointed this out as Dr. Gray®. In one of his papers on the Otariade he justly remarks*:—“ The skull of these animals changes so much in form as the animal arrives at adult and old age, that it is not always easy to determine the species by it, unless you have a series of them of different ages and states to compare.” So much do the parietal crest and other osseous prominences shoot forth in the Sea-bear or Great Sea-lion of some travellers (Ofaria jubata), that between young and old specimens changes as great and characteristic as obtain in the cranium of the Gorilla occur in them. In tracing the development of the skull of this species of Otaria, I have had the advantage of comparing side by side a large number of both sexes and various ages. [| tabulated a series of proportional measurements of the relative growth of different regions, but refrain from introducing the table in this place. Instead I have illustrated, in Series Pl. LXXVII., examples of five different stages of the development, to each of which I append remarks. My figures have been drawn to a uniform scale, quarter natural size; I nevertheless subjoin, in inches and tenths, the absolute length, breadth, and height of each, for greater precision. 5th stage. ¢& very 3rd stage. d ad. (nearly), © ad. Nos. in Cat. Coll. Surg., except sp. 3rd column | 3971 c. | 39718. Z.S.sp.| 3968. | 39714. | 3971 =. Ist stage. | Cie! ars oi '¢ 5 to 20 Crania of Otaria jubata. rive 4th stage. 3 old. 2nd stage. Yearling. old. Greatest length, premaxilla to condyle ...... 6-5 85 | 10-6 | 11:0 12°8 14:3 Greatest breadth 2.0 ioJ.cte ees eves ect 3:9 46 | 65| 58h 75 | 94 Greatest. height, without mandible line cutting 3-6 4-0 4-6 | 47 6-0 | 8-2 THASLO! Oe een en tetas otc ste Mess chasers sos First stage. In the poune skull of a few weeks old the brain-region is in prepon- “fe ate a parietal met nor any considerable develonmiont oe the Riga wigs. “The tfomcere of te large mastoid is well shown in this skull, together with the share which the paroccipital takes in this rough muscular ridge external to the petrosal. he middle surface of the basioccipital is less carinate than in the male. The entry of the carotid canal in the petrosal is more distinct from the jugular vacuity. The broad superorbital processes of the frontal are less angular. The canines and external incisors of the upper jaw are smaller in comparison with the molars. The first and second incisors have bifid crowns. The angle of the lower jaw is produced and bent inwards more than in the male.” 1 T may also refer to a most valuable communication ‘On the Eared Seals,” by Mr. J. A. Allen, Bull. Mus. Comp. Zool. Camb. U.S. vol. ii. no. 1 (1870-71), wherein the author, with occasionally sweeping criticism, has most adroitly woven together many facts concerning sexual variation and changes of the skull in the North- Pacific species. 2 Pp. Z. 8. 1859, p. 360, and Cat. of Seals and Whales in B. M. ®° Ann. & Mag. Nat. Hist. 1868, i. 100. 508 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. derance. It occupies about half the total length, the other half being divided betwixt the orbital region and the face proper or maxillo-premaxillary parts. The entire skull is low, broad, and flat on the top. Superiorly, from occiput to nasals, approaches an equal-sided triangle. The breadth of the mid frontals is not only relatively but abso- lutely a trifle greater than in the aged animal. On the other hand, the prefrontal pro- cesses scarcely extrude. The jugals have but slight arching. The occiput is altogether full, flat, and vertical; the condyles project little. Premaxillee comparatively short and high ; spheno-orbital vacuity shallow, height proportionally great to length. Palate shallow and short. Basioccipital and sphenoid parts smooth, and all other processes small. Mandible with shallow shelving symphysis; a wide ramal arch; condyle short- necked and low-set. Second stage. In this cranium, authenticated as a yearling, there is a sensible change of cerebral to facial and prefrontal areas. Maxillz and premaxille begin to lengthen. Mid frontals narrow relatively to increase of prefrontal processes. The brain-region becomes somewhat quadrangular; occiput rougher and begins to shoot backwards. Temporal groove deepens; jugal arch increases. ‘The permanent teeth in place give more character to the mouth; lengthening and deepening of palate obvious; the hamular processes approach. Eminences of spheno-occipital and other regions show indications of growth, but are not prominent. Condyles and coronoid processes of lower jaw exhibit a tendency to vertical elevation ; mental portion of symphysis inclined to become tuberose. Third stage. Face, orbito-frontal, and brain-division now bear more equal propor- tion; that is, the two former have increased in a greater ratio than the latter. The mid frontals appear more scooped by reason of prefrontal development. By elongation of condyles and concomitant increase of basi- and exoccipitals, the occiput acquires a reverse obliquity to the first stage. The outline of the brain-cavity remains in abeyance, whilst temporal and occipital crests become apparent, though yet moderate. Mastoid and preoccipital eminences acquire a certain prominence. Orbito-jugal arch wider ; premaxille decidedly elongate. ‘Teeth, especially canines, enlarged. Palatal grooving deepened, the pterygoid processes nearing, hence postnares less open. Muscular im- pressions on basioccipital well scooped, basiocciput turning upwards behind. Symphysis lengthened ; upward tilt of ascending ramus. In this stage sexual distinction becomes evident, although there is still considerable resemblance between them. Fourth stage. Here the changes become very notable. ‘The excessive growth of the canines of the male produce rounder, fuller premaxille. Brain-expansion is arrested. Mid-frontal width retrogrades, while prefrontal progresses. ‘The jugal arch expands, its orbital segment deepens, its post upper angle rises; the maxillary surface of orbit gets fuller. Parieto-occipital crests and processes acquire importance; and this causes the after part of the top of the skull to be elevated and no longer smooth and broad. Moreover on each side, at the fronto-parietal suture, bony projections appear. Arching DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 509 of palate and lengthening of pterygoids go on apace. ‘The tympanic bones descend and become laterally compressed, whilst the carotic canal assumes a more vertical direction posteriorly. Meantime the basisphenoid shelves upwards and forwards, the paramastoids roughly bulging out. Growth of the occipital crest alters the back of the skull to a kind of trefoil outline. Increment of the teeth widens the premaxillary region and anterior nares. There is an upturning of the ascending ramus and an inflection of the angle. The bones altogether become more massive and rugose. Fifth stage. As the skull ripens to old age, particularly in the male, all the charac- teristic points of the fourth stage are carried out by excessive growth of processes, crests, and other superficial developments of bony lines, spicules, and nodules. The cavity of the eye looks forwards; the space behind for the temporal and masseter muscles enlarging as fleshy bulk preponderates over cerebral character. It follows that all the aforesaid changes are an exact counterpart of what obtains in the Gorilla. In early youth the brain is functionally predominant. Then the teeth assume importance with a corresponding facial accession. Lastly, whereas brain-incre- ment is apparently arrested, the muscles of mastication, those of the throat and neck, indeed all connected with the head, and therefore involved in the organs of offence and defence, paramountly swell in bulk and strength; nerves and blood-vessels augment proportionally. Thus from the featureless skull is evolved the rugged, immense, and terrible-looking carnivorous cranium peculiar to this and certain other genera of the Fared Seals '. 2. Spinal Column and Thorax. a. Vertebre.—Restricting myself to the Society’s male specimen, its vertebral elements were as follows:—7 cervical, 15 dorsal, 5 lumbar, 4 sacral, and 8 candal; or a total of 59 pieces. The cervicals are all large relatively, the largest of the series. The first 5 or 6 dorsal, from their greater spines and transverse processes, also seem large. ‘The remainder of the dorsals decrease in size as regards height and breadth. The lumbar vertebrae appear of moderate size, the three hindermost being rather the stoutest. ‘The Ist sacral is of fair size; the remainder, with the caudal, form a graduated series, none of which are large. The spinal column (46 inches long) does not seem to hinge on any particular vertebra, all being equally movable by the thick cartilaginous intervertebral disks. The axis is the only cervical with a long spine. The first four retrovert neural spines of the dorsal are longest and subequal; there is no other prominent spine behind. All the inferior processes of the cervical vertebra, as De Blainville* has depicted, are stout ‘ See Allen, as cited, for the genera Eumetopias, Zalophus, and Callorhinus. Dr. Gray, also, in several com- munications to the Society’s Proceedings, has shown cranial alterations in some rarer forms, since the present memoir was read, 2 «Ostéographie,’ plate vil. Atlas, part 2. VOL. VIII.—PART IX. June, 1874. 4B 510 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. but short. The dorsal vertebree present no striking difference from those of Seals generally. Gradually narrowing, the dorsals merge into the lumbar vertebrae, which are likewise larger, but not specially characterized from other Phocine genera. In computing the presence of four sacral vertebree, I am guided partly by the nervous dis- tribution and partly by the fact that the said number bears closest resemblance to each other of the series. ‘Together they are distinguished by their raking neural arches and spines, subequal in length, and lying upon each other almost in an imbricated manner. The foremost has the largest body, the modified great flat-surfaced transverse processes forming a sacro-iliac synchondrosis, a facet of the second assisting. The bodies of the 2nd, 3rd, and 4th are carinate, but, nevertheless, have not the depth of the Ist. The pedicles of their transverse processes are uncommonly squat, a retral bar, however, enclosing an intertransverse foramen. In our adult male animal under consideration, there are eight caudal vertebre re- markably movable upon each other by the intervention of thick interarticular fibro- cartilaginous disks. The vertebra diminish regularly from the first to the last, which is of very small size, and but incompletely ossified. The first two have each backwardly directed spinous processes. The third has two imperfectly formed thick laminar eleva- tions, but no spine. All three of these vertebrae have well-developed transverse processes. From the fourth to the eighth caudal element there are no spinous or transverse processes, slightly raised elevation of the bone alone representing these structures. b. The Ribs.—Of the fifteen pairs of ribs, the Ist, 2nd, and 3rd are the shortest, then follows the 15th. From the 4th backwards to the 9th and 10th, there is a gradual increase in length, from which they decrease as they go backwards. The subjoimed Table gives the respective costal lengths in the young and adult animals. ‘The measurements in each are from the angle to the costal tip :— Ribs. Young. Adult (Z.S.sp.). Ribs. Young. Adult (Z.8. sp.). MSbisiandendtraseas 15 2°7 Oty eres 6-5 10-0 Th Wai afetsretne 21 35 LOG ees Pence 6-2 10-0 SLC! W grote eee 32 52 | LATS ores. 6:2 9-9 AGT siotsvastocess Aol 6:8 PANIES 6 ocome 6-0 9-4 Obie had cone) oe 4-7 78 IES IAW eears ergi Ov, 8:6 GEL se sen ose a3 8-9 DATING sero, etlentie ; 5:2 ted AGL eeoene ares 59 9-1 15th 3-9 6-1 Sihiwaewemt Gall 9:5 The first rib has a stout roundish straight body, with a very slight antero-posterior compression. ‘The neck, set almost at a right angle to the body of the rib, is thick, and markedly grooved in front and behind. The capitulum is of moderate size; it articulates with the anterior part of the body of the first dorsal vertebra, barely im- pinging against the intervertebral cartilage. The prominent tubercle, and its articular DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 511 facet, together nearly } an inch long, in this and the succeeding rib, shoot upwards nearly in the line of the axis of the body itself. Indeed these processes seem almost to form the true termination of the ribs, from which the neck and head proper seem but forked offsets. The second rib diverges slightly from the pattern of the first, inasmuch as it is rather longer, thinner, and possesses a wider sweep or curvature from the angle to the neck. There is just a perceptible indication of a bending backwards or semi-twist at the angle, but not the same flattening and bulging which obtains in the succeeding ribs. ‘The scalene tuberosity, tolerably well marked in the first rib, is diminished and well-nigh obsolete on the second. The third, fourth, and fifth ribs are fashioned not unlike each other, and with but slight individual variation. They present different yet scarcely appreciable degrees of curvature and twist, the body altering in such a manner that what was the anterior surface in the first and second ribs becomes in them the outer flattened surface. Their sternal extremities are more compressed and elliptical in outline than the ribs in front or those immediately behind. ‘The angles of the three ribs in question are better indicated than the others in the series, but none have it well pronounced. The fork- like head and elongated tubercle distinctive of the first two ribs undergoes a gradual change in the third, fourth, and fifth. The neck becomes vertically deeper, less con- stricted, and consequently appears shorter, although not in reality so. The tubercle diminishes in length, and its articular facet acquires a more backward direction. The anterior groove at the angle lessens from the third to the fifth. The enlarged capi- tulum of each assumes an obliquity of condition, and with a fore-and-aft articulating face abuts upon the posterior surface of the body of the vertebree in advance and the anterior surface of its own numerical vertebra. From the sixth to the twelfth costal elements there is a very gradual progressive change in the amount of curvature, and in reduction of the tubercle. The differences between the intervening ribs will be best comprehended by comparing, say, the sixth with the twelfth, rather than attempting to describe the next to insensible modifications which the ribs seriatim undergo. The sixth rib, then, with similitude to the fifth, is long, of moderate breadth and thickness, narrowed and slightly triangular in transverse section about its middle, but flatter and compressed from within outwards, below. It joins the sternal cartilage by a truncated somewhat bulbous end. The outer surface from the angle downwards is plain and smooth, the front and hinder edges gently rounded. ‘The unequal arch of the body is deepest at the angle. ‘The latter is not protuberant but definable, the more readily so as the rib at this part as well as the neck and head is compressed antero- posteriorly. The tubercle is of fair size; the neck and head large, but uniform in diameter. The most notable changes in the twelfth rib are little or no antero-posterior compression, no defined angle, the rib from one end to the other presenting a wide, low, regular arch. The head, neck, and tubercle have decreased in ratio, the division 4B2 512 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. between them being less pronounced. The rib at the angle has lost the semi-twist possessed by the sixth; but instead there is a more regular spiral, so that the outer surface has a somewhat backward inclination below. ‘The sternal extremity is thinned. Surface within and without body biconvex, with sharp antero-posterior edges. The 13th, 14th, and 15th ribs have little or no distinction between head, neck, and tubercle; they are elliptical in their long diameter, weak, slightly concave in arch, the free extremities tapering. They all articulate, with but a single vertebral body. The zygapophysial articulating surface is on their inner sides. Instead of a convex angle there is a shallow concayity in its place, which is very slight in the 135th, a little more so in the 14th, and distinct in the 15th. c. Sternum.—De Blainville’s representation of this bone (‘ Atlas, 1. 1. pl. vii.) calls for a few remarks on my part. ‘These refer to the intersternal and superadded cartilaginous elements. As the above authority shows, there are eight sternal bones, the manubrium being prolonged beyond the first rib; but the attached rib- cartilages are nine in number. In these respects the Society’s specimen agrees. De Blainville’s more aged animal and dry skeleton, however, have misled him—first, in assigning too limited an area for the intersternal cartilages; secondly, in the abutment of the eighth and ninth sternal ribs against the seventh bone instead of behind it on the’cartilage; and, thirdly, in the xiphoid cartilage being narrow and straight, instead of spatulate. These omissions, through a defective skeleton, have to some extent been already rectified from the present specimen, by my friend Mr. Parker’. The manubrium has a flat dorsal and carinate ventral surface, the anterior broader segment terminating in a forwardly projecting blunt cartilage an inch long. ‘The pos- terior segment is much narrower, stouter, and vertically deeper than the anterior portion. ‘The second, third, fourth, fifth, and sixth meso-sternal elements range about one size, and differ from each other chiefly as regards breadth and thickness. From being round, with bulbous extremities, they gradually alter, becoming broader, thinner, and flatter. The seventh piece is unlike the sixth in having an arched instead of trun- cate posterior extremity, the rounded edges thus giving greater space to the inter sternal cartilage, whereby, as aforesaid, the eighth and ninth sternal ribs join it. The “metosteon” of the xiphoid precisely resembles one of the phalanges of the manus, but is thinner; the xipho-cartilage has a short narrow handle, ending in a broad rounded extremity, not quite pyriform, as Parker remarks, and certainly entirely different from De Blainville’s figure. The several bones from the pre- to the xiphosternum measure respectively 2°8, 1°6, 1:4, 1:5, 1-4, 1-5, 1-9, 2-5 inches long. In a young female of the same species which I have had an opportunity of comparing, these bones had the following long diameters * A Monograph of the Structure and Development of the Shoulder-girdle and Sternum in the Vertebrata ~ (Ray Soc. 1867), p. 216, pl. xxx. fig. 7. Witness also fig. 25, pl. Ixxil. of pt. 1. of my own memoir, DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 5138 =2°:0, 0°9, 1:0, 0°8, 0°8, 0°95, 1:1, 1-6. Thus these bones present the same relations as regards size inthe young and olderanimal. It is not so, however, with the cartilages, which in the young Otary are each equal to half the length of the bone, but in the adult no more than a third. The sternal cartilages are thick, long, and flexible; but the last three are shorter than the others, and comparatively free. ‘The first cartilage articulates with the pre- sternal bony facet. ‘The second, third, and fourth are attached to the middle of the intersternal cartilages. The fifth, sixth, and seventh join the intersternal cartilages more obliquely, and are inserted chiefly into the hinder corners of the 4th, 5th, and 6th sternal bones. The eighth cartilage is fixed to the rounded postero-outer border of the seventh bone; the 9th to the middle of the cartilage. The cavity of the thorax and abdomen enclosed by the ribs, is long, deep, and narrow, according as the ribs are expanded or otherwise, heart-shaped, =22 inches long. ‘The ribs either stand out or are flattened. ‘This is chiefly permitted by the looseness of the cartilaginous and ligamentous union, also length and flexibility of the sternal cartilages. 3. Bones of the Extremities. a. Pectoral Limb.—Scapula. This has not the arched or semilunar shape of the Common Seal, but is a broad irregularly trapezoidal thin bone. It measures in our specimen 6°5 inches from the glenoid head (the cartilage 7 sitw) across to the middle vertebral or posterior border, and it is 8 inches in diameter between the superior and inferior angles. The spine is of moderate nearly uniform height, and possesses a downward slant, overarching very slightly the infraspinous fossa. It is carried onwards to within 3 an inch of the glenoid cavity, whence an acromion process rather broader than the spine itself reaches almost to the articular fossa. In the recent state a ligament converts this acromial arch into a foramen. ‘The glenoidal cavity is shallow and more oval in shape than in Phoca vitulina. The neck is very short, broad, and stout. Only a rudiment of the coracoid process is present. The supraspinous fossa occupies the upper three fourths of the bone’. A slightly raised ridge proceeds from the upper third of the neck backwards and towards the superior angle, dividing the supraspinous fossa into two shallow concavities. The narrower, but deeper, infraspinous fossa has the oblique ridge and groove for the teres major distinctly marked. The space lodging the infraspinatus muscle is hollow, and not convex. Humerus. Figured in three different views by De Blainville (op. cit. pl. viii.), is short, stout, and peculiar-looking from the great development and prominent nature of the deltoid eminence. The greatest length of the bone in a straight line is 63 inches, being + of an inch less than the radius, and 1} inch shorter than the ulna. The 1 Vide Cuvier, ‘ Ossemens Fossiles,’ tom. y. pt.i. p. 224, and De Blainyille, op. cit. text, tom. ii. p. 23, Atlas,’ vol. ii, pls. iii, & viii, 514 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. axis of the three-faced shaft is nearly perpendicular, though at first sight it does not appear so, the deltoid projection giving it outwardly somewhat the contour of the letter S. The latter forms a thick anterior projecting and somewhat laterally com- pressed plate of bone extending from the root of the unusually greater tuberosity downwards, mesially, four fifths the length of the shaft. Head and neck sessile. Con- dyloid ridges short, but giving great lateral breadth to the lower half of shaft. Inner condyle most marked; eminentia capitata and inner trochlear eminence the reverse. The further positions of the bones of the elbow-joint, and their singular gliding movements upon each other, I discussed when treating of the ligamentous system (consult pt. 11. vol. vil. p. 581). Ulina and Radius. Throughout the Pinnipedia the ulna is hatchet-shaped, altogether flattened, especially the olecranon (as the blade). Slight modifications distinguish the different families and genera (witness Cuvier and De Blainville’s illustrations &c.). In Otaria jubata the outer extensor surface of shaft is gently convex in its axes, the inner flexor is concave; distal epiphysis conical. The even-surfaced greater sigmoid notch is almost vertical, with the exception of a small inferior projection (=the coronoid process) upon which the inner knuckle of the humerus plays; and on the radial side of this projection an oblique shallow concavity represents the lesser sigmoid notch. A widish inward scoop separates the humeral articulation from the top of the olecranon process, which latter, thinning, sweeps backwards, terminating in a dependent angular process. The radius has a well-defined neck, short but large and wide shallow head. From the upper third the roundish shaft widens and flattens to its massive lower extremity, 24 inches broad, with thickness in proportion. Carpus, Metacarpus, and Phalanges. Of the seven carpal bones the amalgamated scapholunar is the most remarkable, on account of its great size and of its claiming the major share of the articular surface of the first row of bones. It is in opposition with all the bones of the second row, the cuneiform, and radius, in all six; but it plays against these virtually by three faces. The radial is large and convex; the face in con- tiguity with the os magnum and unciform is somewhat vertically scooped, a mesial ridge defining the province of each bone, whilst the cuneiform impinges against the posterior corner of the latter; lastly, the trapezio-trapezoidal is extensive, rhomboidal-outlined, concave from without inwards, and convex from above downwards. It is this peculiar disposition of the latter, in unison with a certain oblique or excentric movement of the parts, which enables the animal to use its fore flipper on land as a foot ; for the proximal carpal row is then raised from the horizontal basal line, as in a great measure is the unciform. Thus the wedged-in magnum, the trapezoides, and the trapezium of the carpals form the base of support; and that also accounts for the singular radial flop with which the manus is laid down in walking. According to the amount of bend of the wrist-joint, so does the cuneiform in a lesser or greater degree come into connexion with the bones. Its postero-outer face receives the pisiform and point of the ulna in a DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 515 wide hollow ; the inner glides upon the radius; a narrow corner of the anterior impinges against the scapholunar, its remainder articulating with the unciform ; and an outer facet partly accommodates the fifth metacarpal as the manus is twisted outwards. The pisiform is a small bean-shaped bone, its free end directed outwards, its attached end lying upon the epiphysis of the ulna and the cuneiform of the four articular surfaces presented by the trapezium ; that towards the second metacarpal is a mere corner facet. The trapezoidal is smaller than the trapezium, its palmar surface being very consider- ably narrowed. It just touches the third metacarpal, besides its ordinary facets for scaphoid, magnum, trapezium, and first metacarpal. The os magnum is the least-sized bone of the distal row, and, reversely from the last, has a narrow dorsal and broader palmar surface. It appears not to come into contact with the second metacarpal, and sinks in obliquely and below the scapholunar. Thus when the manus is planted on the ground the latter bone overrides it in great part. The unciform is about equal to the trapezoides in magnitude. It is surrounded by five bones, the fifth metacarpal more usually constituting its outer boundary. The metacarpals are of most unequal dimensions, that of the pollex being of inordi- nate proportions. The lengths from Ist to 5th are as follows:—4:25, 3, 2°3, 2, and 1-9 inch. The first is by far the broadest, thickest, and flattest; the third thinnest and roundest. The fifth differs from the fourth in being a wider bone. The proximal ends of the outer four are enlarged and tuberose; the width of the innermost (first) subdues its otherwise bulky character. The phalanges, of normal number, bear a relation to the size of the metacarpals; that is, the innermost is largest and longest, the fifth digit a trifle stronger though shorter than the fourth. The proximal phalanx of the thumb is powerful, its distal one a short flat figure of eight; respectively they are 3-9 and 1:5 inch long. The lengths of the remainder of the series are:—second digit 2:7, 2-2, 1; third digit 1:9, 1-6, 1; fourth digit 1:5, 0°8, 0.3; fifth digit 1:3, 0-3, 0-2 inch. The spatulate cartilages and that extraordinary one of the pollex, which form the digital extremities, I drew attention to and figured in my former anatomical contribution. b. Pelvic Limb.—Pelvis. The long axis of the entire pelvis is almost identical with that of the spinal column, and even in the strange attitude of walking it accords with the lumbo-caudal region’. Tlio-pubic and ilio-ischial angles cannot be said to obtain. Each innominate bone approaches posteriorly so as to produce a long narrow V-shaped pelvis, and with such variation in the thickness of the bones that the brim is lozenge- shaped. The ischium and pubis are narrow bars uniting in a thin rounded plate the tuberosity, and enclosing a lengthened oval obturator foramen. Their acetabular ends thicken; the acetabulum itself is large but not deep. ‘The ilium is a broader strip of bone, slightly outturned anteriorly, its sacral border inturned, and with moderate sacro- * Cuvier (J. ¢. p. 226) briefly distinguishes between the pelvis of the Earless and Eared Seals, a point which Allen in his paper (J. ¢. p. 27) with justice lays great stress on as characteristic of the two groups. 516 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. iliac synchondrosis. Measurements:—Extreme pelvic length 7:3 inches, ilium 3:1, pubis 4:2, as is also ischium to mid-acetabulum; the latter 1:3 long, anterior iliac angles 3:3 apart, mid iliac breadth or depth 1:2, line cutting acetabulum 1°7, mid ischio-pubal 1:3. Diameters of brim—conjugate 4:7, transverse 1:5, oblique 5:3. Diameters of outlet—antero-posterior 1-4, transverse 0-4. Femur and Patella. The former, at its upper end, has head and trochanteric eminence on a level simulating one another—and neither prominent, from the antero- posterior flattening and breadth of the short shaft. The intercondyloid fossa is shallow, the innermost knuckle largest, and both rather square in figure from being truncate below. Femur is 4 inches long. Patella small, rounded, and with a flat articular surface. Tibia and Fibula. The straight rodlike fibula usually stands quite behind the tibia ; its narrowed shaft is sharply triangular. Head badly defined, smaller end more expanded. The tibia has a forward bend, a somewhat laterally compressed stoutish shaft, and subequally enlarged extremities. The articular end opposed to the femur is smooth and pretty equal-surfaced ; but it shelves downwards, backwards, and outwards. This posterior inclination is most serviceable, and, indeed, enables the femur to be bent on the lower limb at a very acute angle without depriving the muscles of their power of action in walking. Moreover, along with unusual freedom of the femur, it contributes to the limb being thrown back and up in a line with the tail as in the act of swimming. There is a short inner malleolus; and the adjoining astragaloid face has double facets. Extreme length of tibia 8-2, of fibula 6°5 inches. Hind Foot. When the animal is on all fours the tarsal bones, of the normal number, offer perhaps less striking and fewer, but as singular points worthy of notice as the carpus. The entire sole (and not a segment of it) is laid on the ground plantigrade- fashion in walking. Both astragalus and calcaneum are low. Cuvier’s words ((. ¢. p- 226), so applicable to Otaria jubata, will bear quotation. He says :—* L’astragale des phoques est trés-extraordinaire, en ce qu’au lieu d’une poulie plus ou moins creuse dans son milieu il offre 4 la jambe une poulie convexe formée de deux faces, qui font ensemble un angle saillant comme un toit, et dont lune répond au tibia, et Pautre, qui est plus grande, au péroné. Cet os n’a pas seulement une apophyse en avant pour le scaphoide, mais il en a une autre en arriére terminée par une tubérosité et formant une sorte de talon interne, de maniére qu’en voyant l’astragale isolé on croiroit que c’est le caleaneum.” I may note more particularly of the present specimen that the horizon- tally ovoid fibular facet looks backwards and inwards, and there is a certain amount of the same obliquity apparent in its tibial concavo-convex facet. These dispositions . concurrently adapt themselves to the peculiarities of tibia and fibula. The plantar surface of the os calcisis roughened and moderately convex ; the short calcaneal process seems to have an inward tilt. It is not altogether, as Cuvier observes, that the calcaneum is placed outside the astragalus, but rather that the two bones have a DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 517 constricted X-position to one another, or together are semirotated, lying slanting inwards on their short axes. These anomalies have a most important bearing, inasmuch as mechanism for swimming and diving are concerned : and they well explain, religated with musculo-tendinous' accessories, how it is that the hind foot acts like a pivot on the heel when walking or running. It is in fact an adjustment of instrument for terraqueous locomotion. ‘The awkward pedal defect colloquially known as “flat-footed” in man is a kind of first stage towards the Otary’s condition, though through hgamen- tous rather than osseous conformation in his case. The Earless Seal’s incapacity to use the hind foot on land depends more on the different proportion of femur to leg-bones, and lowered attachment of tegumentary caudal expansion, than to absolute difference in the construction of the bones forming the ankle-joint. In the Sea-lion the cuboid, naviculare, and entocuneiform are each fair-sized, the meso- and ectocuneiform small and very much laterally compressed, particularly the latter, which is indeed a diminu- tive bone. With respect to the metatarsals, the hallucial is longest and strongest, the fifth a shade less, the three intermediate much slenderer and a trifle shorter. Not taking into account apical cartilages, the bones of the digits terminate somewhat subequally—the first, however, being shortest, the fifth next, and the third by a grade the longest. It results that the three middle digits have altogether the longest phalangeal bones: but the proximal phalanx of the hallux is in itself decidedly the longer and stouter bone compared with the proximal of the other digits. The second, third, and fourth ungual projections are best marked. Il. Tue Nervovs System. 1. Remarks on the Extraction of the Brain and Membranes. Tue strong fibrous pericranium having been divided, the bone of the cranial vault was carefully sawn through ina nearly horizontal line, extending on each side from the upper arch of the foramen magnum forwards, close to the postfrontal prominence. At the latter part the saw was again used vertically and transversely, so as to cut the anterior points of the horseshoe-shaped horizontal incision. When the calvarium had thus been loosened in its osseous circumference, it still remained firmly fixed by the bony tentorial lamella. This latter was then broken through by manceuvring in a wriggling manner backwards and upwards, and the brain-pan removed. The great difference between the thick osseous protection afforded to the cerebral mass above, and the thin side walls, became strikingly evident on the calvarium being raised (see figs. 9 and 10). It would appear as if the powerful temporal and masseter muscles, besides being massive fleshy engines of mastication, must also, with their fatty and 1 For corroborative testimony refer to the various paragraphs in pts. i. & il. of these researches, on the Walrus and Sea-Lion. VOL. VIII.—PART IX. June, 1874. 4c 518 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. cutaneous coverings, act as buffers to the delicate temporal walls, which, in some places, do not exceed a line in thickness. Thus, while the brain is provided against lateral concussions, the very utmost limit is given it as regards breadth, and this without diminishing the space necessary for the muscular apparatus, or increasing the width of the hinder portion of the head, which altogether is comparatively narrow and elongate. On the dura mater being longitudinally divided and laterally reflected, a sketch was made of the brain in situ. In this way the upper convolutions, sulci, and general rela- tion of parts previously to change of position were secured. After this the brain and a small portion of the upper part of the cord were carefully removed in the usual way, then weighed with the membranes, and preserved in spirit. The dura mater of the base being left within the cranium, and the calvarium replaced, an accurate model of the interior was obtained by filling the cavity with plastic mate- rial. From this a mould was formed, and, lastly, a plaster of Paris cast derived there- from. As is well known, the recent brain immediately on removal alters in shape ; and still more so, as Marshall’ has accurately noted, does the preserved encephalon change remarkably in the relations of its parts. A photograph could not conveniently be taken at the moment. ‘The figures here given, therefore (figs. 38, 39, & 40), of the lateral, upper, and basal views, are rigorously measured outlines, by my friend and artist Mr. Berjeau and myself, of the intercranial cast, filled in their details from the shrunken brain, corrected by the sketches made of the organ in its fresh condition. If not perfect counterparts, the figures will be found close approximations to the natural aspect of each view in question. The longitudinal and horizontal sections (Pl. LX-XIX. figs. 44, 45) are from the preserved hardened brain, very slightly modified by reference to a similarly divided soft intracranial model. It is but proper for me to express my sense of obligations to recent workers on cerebral anatomy, among whom more particularly may be mentioned Leuret*, Gratiolet*, Dareste’, Owen*, Huxley’, Flower’, Marshall*, Turner’, and Rolleston”. 2. The Dura and Pia Mater. The most external fibrous cerebral envelope, the dura mater, is firm and of moderate thickness. Its upper surface is very irregularly indented, corresponding as it does to the greatly convoluted brain, and more particularly to the unequally hollowed and ridged bony vault. Minute vascular channels exist plentifully over the greater part of 1 Nat. Hist. Review, 1861, p. 298. > Anat. Comp. d. Syst. Nerv. Paris, 1839-57. 3 Mém. sur les Plis céréb. de 1Homme Ke. 4 Ann. Sc. Nat. 4th ser. iii, 1855, p. 73. 5 Trans. Zool. Soc. vol. i. 1833, “ Cheetah ;”’ and his ‘ Anat. of Verteb.’ vol. i. &c. * Brain of Ateles, P. Z. S. 1861, p. 259: his Hunterian Lectures, &e. 7 Phil. Trans. 1852, p. 185. Trans. & Proc. Zool. Soc., various papers. 8 Phil. Trans. 1865, p. 501. ° Proc. Roy. Soc. Edinb, 1865-66, vol. v. p. 578, de. 10 Nat. Hist. Review, 1861, p. 201. DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 519 the superficies, especially at its hinder portion. The venous sinuses are prominent, and fit into the remarkably deep grooves already mentioned in the description of the interior of the cranium. ‘There is a considerable thickening of the dura mater as it passes out of the foramen magnum backwards towards the spinal canal. Vascularity also distin- guishes the pia mater, otherwise of an ordinary character. 3. The Brain. a. Its outward aspects and dimensions—The general characteristic feature of the brain of Ofaria, looked at on its upper surface, is its comparative squareness—in this respect differing from the more common ovoid form of mammals generally, as well as from the somewhat circular contour which it assumes in Phoca and particularly in Cetaceans. This quadrilateral configuration is chiefly produced by the abrupt trun-’ cation of the frontal and occipital lobes respectively, their outer corners being con- siderably angular, or but very moderately rounded. The lateral margins are deeply indented about their middles; and the fronto-parietal portions are less prominent than the temporo-occipital ones; nevertheless they, on the whole, still lend something to the general quadrilinear aspect of the entire encephalon. Notwithstanding what has been Said, each cerebral hemisphere superiorly presents a reniform outline, the deeply indented Sylvian fissure being equivalent to the hilus, and the straight-edged longi- tudinal fissure to the dorsum, The olfactory bulbs are large, and mesially project considerably forwards. ‘The posterior lobes of the cerebrum are tolerably equal in dimensions: the left may be slightly longer than the right; but this was not clearly appreciable by measurement, though appearing so to the eye. Unlike some of the so-called higher forms of Carnivora, the posterior cerebral lobes all but overlap the cerebellum laterally, as Huxley has recorded is also the case in the allied genus Trichechus. 'The actual amount of backward projection of the outer cerebellar lobes is little more than 0:1 inch. Mesially, however, the superior vermi- form and superior posterior lobes of the cerebellum are more exposed, have a triangular form 1-1 inch long and 1:3 inch broad, and reach slightly further back than the external lobes. The cerebral convolutions are numerous and well developed, giving this upper sur- face quite a sinuous appearance. ‘There is a certain amount of asymmetry between the halves; but this shall be described hereafter. The brain is highest behind, or at the junction of the occipital with the parietal lobes; and from this it inclines downwards and forwards, as also more steeply outwards. Measured from the anterior extremity of the olfactory lobe backwards in a straight line to the most projecting part of the cerebellum, the total length is 4°6 inches. The dia- meter across the parietal lobes is 3-2 inches. The extreme longitudinal axis of each moiety of the cerebrum is 4inches. The greatest transverse diameter of the brain, which is about the middle of the occipital lobes, is also about 4 inches. Thus the length of 4c2 520 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. each hemisphere exactly corresponds to the breadth of both, taken at the hinder half of the brain. And although the frontal half is, as shown, somewhat narrower, yet the above measurements bring out what is the impression at first sight conveyed to the eye —namely, that the brain altogether approximates to an equal-sided figure. The lateral aspects are as remarkable as the superior one, and more clearly demon- strate the infracerebral position of the cerebellum. In this view the entire brain possesses somewhat of an oval shape, the anterior portion of the frontal cerebral lobe narrowing rather angularly, while the rounded, bulbous olfactory surface projects beyond; and together they have considerable vertical depth. Each occipital lobe tapers backwards with a semicircular outline, the inferior border being the straighter of the two. The temporal lobe is broad, tolerably vertical, or only inclined moderately ‘forward ; in front of it a wide and deep depression exists, the Sylvian fissure with its marginal convolution. As in the upper view, the hemispherical segment behind the aforesaid depression or constriction is seen, when viewed sideways, to be decidedly convex, the most protuberant point being the upper part of the temporal lobe; but on the contrary the anterior or frontal segment is remarkably flat and perpendicular.