Art. XIII.—Notes on Gogia breviceps, the Lesser Sperm Whale.
[Read before the Otago Institute, 8th October, 1901.]
On the 30th August, 1900, I heard from Mr. Stronach, of Dunedin, that a small whale had been beached at Purakanui, and at once arranged to go down next day with the taxidermist, Mr. E. Jennings, to inspect it. On our arrival we ascertained that the whale had been driven ashore on the preceding Friday—just a week before. We obtained the services of Mr. Ewart, the fisherman living at the entrance of the bay, who rowed us across to the sandy spit that projects
from the north side of the bay, and showed us the whale. We found the carcase just above high-water mark, nearly imbedded in sand, which had thus preserved the animal from decay, so that it appeared quite fresh. On removing the sand we discovered that the animal had been a good deal cut about—the head had been disarticulated from the vertebral column, and lay near at hand; the lower jaw, however, had been removed, and the top of the head had been injured by the removal of the little spermaceti contained there. The dorsal wall of the body had, likewise, been cut away for the blubber, and with it the dorsal fin. The tail-flukes were also missing, and the abdomen had been opened by a cut through the right sternal ribs, and the viscera lay outside the body.
Owing to the damage done I was unable to trace the true outlines of the body, or to locate the dorsal fin. This is the more to be regretted since specimens of this whale are rare; but fortunately Von Haast was able to give some further details of his specimen. Through the kind offices of Mr. Ewart I was, however, able to obtain the flukes from the Maori who had first discovered the whale, and who had cut away the blubber, &c.; and at a later period I obtained the lower jaw from a fisherman, who had retained and cleaned the bone as a “curio.” Thus I obtained the entire skeleton—not a bone was missing.* The carcase was conveyed to Dunedin, together with some of the viscera—the stomach, larynx, generative organs—an account of which I have forwarded to the Zoological Society of London.†
The “short-headed sperm whale” has been described from our seas in the Transactions by Dr. Von Haast under the name of Euphysetes pottsn, but cetaceologists are now agreed that the various whales described as various species—Euphysetes simus, Owen, from India; Euph. grayii, Wall, and Euph. macleayi, Krefft, from the Australian seas; K. floweri, Gill, from the American coast of the North Pacific; and our New Zealand form—are all members of one and the same species—viz., Kogia‡ breviceps, originally described by De Blainville from a specimen from the Cape of Good Hope.
The various differences relied upon by these authors as of specific value are merely such as are due either to differences of sex or of age, or individual variations in the various specimens taken in various localities.
The specimen under consideration was a male, not quite
[Footnote] * With the possible exception of the pelvic bone.
[Footnote] † See my papers—(1) “On the Larynx of certain Whales,” P.Z.S., 1901, vol. i., p. 278; (2) “On the Anatomy of Cogia breviceps,” 1901, vol. ii., p. 107.
[Footnote] ‡ So spelt by Gray; but Flower, in his text-book on mammalia, spells it “Cogia.”
fully grown, measuring 8 ft. 9 in. from tip of the snout to the bottom of the notch in the fluke; Von Haast's was a young female, the length of which was only 7 ft. 2 in.* I took no measurements of girth, as the animal was too much injured for such measurements to have any value.
The flipper, or pectoral limb, measured 14 in. in a straight line from base to tip, or 15 in. along the slightly curved anterior margin. Its breadth was 5½ in. across the widest part, and 5 in. across the base. The form of the flipper is shown in the figure. The anterior margin has a regular, slightly convex curve; the posterior margin is angulated, the angle being rounded, and enclosed by a shorter proximal limb of 4 in. and a longer distal concave limb of 8 in. in length.
The tail-flukes measured 2 ft. 3 in. across their ends; each fluke is 12 in. across (parallel to the axis of the body) in its widest part; the median notch between the two flukes is 5½ in. deep, measured from a line joining the two tips of the flukes.
The head measured 1 ft. 4 in.—in other words, is rather less than one-sixth the total length of the body, in which it is contained six and a half times.
One of the most interesting of the anatomical features is the asymmetry of the blowhole and of the structures related to “spouting.” The single blowhole, or left nostril, lies on the upper surface of the head; is crescentic, with the convenity forwards and outwards, and therein differing from the usual form in Odontocetes. The distance between the horns of the crescent is 2½ in.; the inner (mesial) horn being rather further forward (1½ in.) than the outer one, and about 12 in. from the tip of the snout (measured after the blubber had been removed). Von Haast states that the “slit was 2 in. long, of which 1½ in. was on the left side and½ in. on the right side.” In my own specimen it appeared to be wholly on the left of the middle line.
Without going into details, which I have published elsewhere, I may briefly describe the apparatus connected with the blowhole. The crescent leads into a wide, shallow pit or vestibule, closed by a fleshy valve, on raising which the two nostrils are seen. The left one is a wide crescentic aperture leading into a wide circular and simple canal, which passes directly downwards through the skull to open into the naso-palatine canal which communicates with the mouth by the posterior nares. The right nostril is, however, very small and slit-like, situated at extreme right corner of the vestibule, and the canal into which it leads passes obliquely forwards and down-
[Footnote] * This is precisely the length given by Mr. Elliott, who supplied Professor Owen with the material on which his paper is founded. (See Trans. Zool. Soc., vi., p. 172.)
wards to open into a large chamber, 5in. by 3 in. in diameter; thence a short canal passes into a second chamber of less dimensions, the hinder wall of which rests against the roof of the skull. The anterior wall is fleshy, and evidently capable of considerable movement in contraction and expansion. This lower chamber is somewhat pear-shaped, with the narrow end downwards, and thence a very narrow short canal opens into the naso-palatine canal.
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Owing to the removal of the lower jaw I am unable to describe the form, size, or position of the mouth, which is described by other zoologists as small, and situated some distance from the tip of the snout. The lower jaw is provided on each side with thirteen conical, pointed, and slightly curved teeth; each tooth fits into a pit in the gum of the upper jaw. In the upper jaw are only two teeth, situated far forward, and carried by the premaxillary bones. On the right side the tooth projected from the gum for 3/16 in., but the left tooth had only just “cut” the gum, so that only the extreme tip projected.
The alimentary canal had been torn out of the body, but the stomach was preserved and the intestines and contents examined. The length of the intestine is about 32 yards, of which the small intestine measured 30 yards; then it dilated to form a great sac a yard or so in length and 10 in. across, filled with dark-brown, almost black, fluid of considerable consistency, which consists of “sepia,” or contents of the ink-sacs of the cuttlefishes upon which the whale had fed. The stomach contained great quantities of squid-beaks, lenses of squids' eyes, and pens of squids. Von Haast's suggestion that the whale feeds on “smaller hydroid zoophytes” is an error, due partly to the absence of beaks in the stomach of his specimen. Van Beneden and Gervais suggest, from the form of the teeth, that Cogia probably feeds on fishes (p. 354) rather than cuttles. I found no trace of fish.
As I have above indicated, I was able to obtain a complete skeleton.* There is one bone which, however, may have been present—the pelvic bone. But I carefully examined the region in which it should lie, and, moreover, removed and dissected the penis, of which an illustrated account appears in another journal.†
[Footnote] * This skeleton has been purchased by the Cambridge University Zoological Museum; and an illustrated account of certain bones has been laid before the Zoological Society by me, and will be published in a forthcoming volume of the Proceedings of the Society.
[Footnote] † P.Z.S., 1901, vol. ii., p. 107.
Now, as is known, certain structures—the corpora cavernosa—are attached to the pelvis in mammals, and in some whales the bone is almost imbedded in this structure; but in Cogia I was unable to find it. On the other hand, Wall describes and figures the pelvis as consisting of four bones in a transverse row, an inner and outer, more or less quadrangular plates, on each side. I feel certain that no such bones existed in my specimen, for I looked specially for them. We may, I think, conclude that the pelvis is absent, and in this respect Cogia differs from the sperm whale.
The length of the vertebral column when the cleaned bones were set in position touching one another is 6 ft. 8 in., which, with the skull, measuring 1 ft. 3½ in., gives a total of 7 ft. 11½ in. for the axial skeleton. To this must be added several inches for the intravertebral discs. The epiphyses are separate.
The seven cervicals are in this genus entirely fused; and the usual evidences of the individual vertebræ, such as neural arches, spines, and transverse processes, are almost entirely obliterated. The atlas has its outlines distinct enough, and the neural arch and transverse process of the second vertebra are evident, while the seventh is also well marked out, but the intervening four vertebræ are so fused that it is practically impossible to distinguish their boundaries:—
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|Greatest Length.||Greatest Height.||Height.||Breadth.|
|45 mm.||107 mm.||30 mm.||38 mm.||126 mm.||57 mm.|
In this case the total length is measured along the ventral mid-line; the height, from the ventral mid-line to tip of the neural spine, which projects backwards from the hinder end of the mass, which is, really, the height of the 7th cervical vertebra. The anterior central breadth is across the facets from the occipital condyles.
This cervical mass is followed by forty-six free vertebræ, giving a total of fifty-three vertebræ, of which thirteen are thoracic, bearing ribs,* nine are lumbar, and twenty-three are caudal, of which the first thirteen bear chevrons. Von Haast's
[Footnote] * The 13th thoracic has on left side a small articular surface at the end of the transverse process, but on the right side this is absent.
specimen contained only fifty vertebræ, which are made up of seven cervical, twelve thoracic, eleven lumbar, and twenty caudal, with only eight chevrons. Wall's Australian specimen contains fifty-one vertebræ—seven cervical, fourteen thoracic, nine lumbar, and twenty-one caudal—with thirteen chevrons; Krefft's, fifty-five vertebræ—seven cervical, thirteen thoracic, nine lumbar, and twenty-six caudal—with ten chevrons. In Wall's specimen the 14th rib is represented in the figure as quite a small nodule, entirely unconnected with the vertebral column, and is only 11½ in. in length, in contrast to the 13th rib, measuring 11½ in. In Krefft's specimen, too, the last (13th) rib is much smaller (4 in.) than the 12th (12 in.) on the left side.
In addition to the twelve pairs of long ribs, the measurements of which are given below, I found amongst the débris of the macerating-pan, which had been carefully preserved by the taxidermist (Mr. Jennings, who took a very great deal of trouble to preserve every piece of bone and cartilage), a small bone, measuring 1½ in. in length (i.e., 35 mm.) by about ⅜ in. (9 mm.) in greatest breadth: this appears to be a 13th rib of the left side. One end of this small bone is broader than the other, and appears to be the lower end. One surface of this bone is flat, the other strongly convex, and the general form agrees precisely with the shape of the 12th rib just below its curved region. Moreover, we found a long piece of cartilage, 4 in. long, broader at one end and pointed at the other, flattened and curved, which I believe to be the unossified distal portion of the rib. The proximal cartilage which may have connected this rib to the 13th thoracic vertebra is, unfortunately, missing; possibly the connection was ligamentous. We found no corresponding bone for the right side, but a short piece of cartilage, about 1 in. in length, corresponding to the upper end of the aforementioned cartilage, indicating the possible existence of a 13th rib on right side. There can be no doubt but that, except in a very carefully macerated skeleton, this last rib would be overlooked, and in skeletons found on shore there is little likelihood of its being preserved.
The figure given by Wall (who only found the ribs of right side and the 1st left rib) is wrong, in that he places this 14th rib in line with the lower end of the preceding one; it should be in line with the upper end, just where the curve commences to descend.
Van Beneden and Gervais, in the brief account (p. 515) given of an incomplete skeleton from Japan, find thirteen thoracic vertebræ, recognisable by articular facets for ribs, but add “there may have been fourteen pairs of ribs, the last being free.”
|Vertebra.||Length.||Height.||Breadth.||Transverse Diameter.||Vertical Diameter.|
|Anterior Face.||Posterior Face.||Anterior Face.||Posterior Face.||Anterior Face.||Posterior Face.|
The foregoing table gives the principal measurements of the vertebrae: these are in millimeters, and taken with calipers. The length of the vertebra is the length of centrum measured from the centres of the epiphyses. The height is the greatest distance from the ventral surface of the centrum to tip of the neural spine. The breadth is taken from tip to tip of the tranverse processes where they exist, or across the widest part of centrum where the transverse processes are absent. The diameters of the centrum, or body of the vertebrae, are taken at the anterior and posterior extremities of the body itself.
It will be noted that the bodies of the vertebrae increase in size up to the middle of the lumbar series, and then decrease. This increase is quite gradual, but in the case of the decrease in height there is a sudden drop at the end of the lumbar series, owing to the sudden diminution of the neural spine. The bodies of the vertebrae are much larger in the middle of the vertebral column, the greater number of caudals having larger centres than the thoracics, which are relatively slender.
The hinder caudals, as in other whales, are incompletely formed—i.e., the neural arch is imperfectly closed above; the 11th caudal has no neural spine, though the right and left neural laminae meet, but in the 12th they do not meet, and by the 14th they are practically non-existent, so that the 15th et seq. consist of centrum only. The lumbar vertebrae exhibit a peculiarity, which appears to be characteristic, in the presence of the anterior and posterior prominences on the ventral surface of the centra, in the mid-line.
I have not thought it necessary to reproduce my detailed notes as to the form of the individual vertebrae. They are, on the whole, closely similar to those of the sperm whale (Physeter macrocephalus) as described by Flower; while the general appearance of the entire skeleton has been figured—more or less imperfectly, it is true—by Owen, Wall, Van Beneden and Gervais, and Von Haast.
The Chevrons.—The usual form of these bones is Y-shaped—i.e., each consists of a right and left lamina meeting at an acute angle, and the fused plate so formed is produced down-wards to form a keel. But there are variations of this type. The 1st chevron is U-shaped, each lamina having an outer face which is very convex; and, further, they only meet over a comparatively short area, so that there is no keel. The 7th, again, is V-shaped, the keel being practically absent; while the 12th is a short half-cylinder of bone with a shallow groove on its upper surface. It will be noticed that the 3rd chevron is the largest of the series.
|—||Vertical Diameter (Height).||Antero-posterior Diameter (Length).||Transverse Diameter (Breadth).|
The Ribs.—of the thirteen ribs four are connected to the sternum by sternal ribs. The first vertebral rib, as in other cases, is much stouter and shorter than the following. It is broad, compressed antero-posteriorly and expanded distally. It has a distinctly marked “angle” near the proximal extremity, below which it curves suddenly downwards and inwards to meet its sternal rib. The proximal extremity bears distinct capitulum and tuberculum, as Von Haast noted, and herein our New Zealand specimens appear to differ from Wall's specimen; while in Physeter, which is its nearest ally, Flower states that these are not separate and distinct.
The two articular facets are nearly of equal size, though the capitulum is slightly the smaller. They are separated by a small “neck” measuring 14 mm. in length. This capitulum articulates with a conspicuous facet at the side of the hinder end of the cervical mass—i.e., of the 7th cervical vertebra. The tuberculum, of course, articulates with the transverse process of the first thoracic.
The 2nd rib is much longer, but less stout; it is flattened and broad, however, like the first.
The capitulum and tuberculum are separated by a distance of 20 mm., the former being rather the larger facet of the two. The angle is well marked, but less acute than in the first rib, and the curvature is more gradual.
In this and the following four ribs the capitulum articulates with the posterior end of the preceding vertebra only, and not with its own vertebra.
The 3rd to 6th ribs are practically similar, but the curvature is different, for in the first place the angle is less
marked in all the ribs following the 2nd, and the curvature is more gentle and regular. The upper region, instead of being horizontal, is inclined downwards, and this general form is retained by the rest; but the convexity of the curve decreases. so that the ribs, as traced backwards, tend to become straighter.
In the 7th and following ribs the capitulum ceases to articulate with any vertebra; it is bluntly pointed, and probably connected by ligament to the column.
The 13th rib has been described.
There is no important difference between the ribs of the right and left sides. I add a table of measurements. The length of the rib is measured in a straight line from the inner margin of its articular extremity to the inner margin of the distal extremity. The “curvature” is really the distance of the most remote point on the inner margin from the line joining the two extremities of the ribs.
The sternum has not, as far as I am aware, received a detailed description by any previous author, for it was only partially recovered for Wall's specimen, and Von Haast makes no mention of it. In the present specimen it and the sternal ribs are complete. It consists of three sternebrae, the first and second formed of a single bone, the last of a pair of small bones imbedded in cartilage. There are four pairs of sternal ribs, measuring respectively 90 mm., 75 mm., 60 mm., and 30 mm.
The total length of sternum, including the cartilage at each extremity, is 260 mm.; the greatest breadth, measured just behind the articulation of the first sternal rib, is 155 mm.;
[Footnote] * Together with cartilage above and below.
and the least breadth, measured across last sternebra, is 45 mm.
The cartilage of this and other parts of the skeleton has been treated by the glycerine-gelatine method, and retains its true form and relations; but, since the cartilage is not likely to be present in all skeletons, I give the measurements of the bony parts as well:—
|First bony sternebra—||Mm.|
|Length (lower surface)||90|
|Breadth (anterior end)||100|
|Breadth (posterior end)||60|
|Thickness (dorso-ventral) in middle||10|
|Second bony sternebra—|
|Breadth (anterior end)||54|
|Breadth (posterior end)||51|
|Third bony sternebra—|
The anterior end of the sternum is slightly bent upwards, but otherwise the bones are flat, with rounded lateral margins. The 1st sternebra is thinner at anterior than at posterior end. The thickness increases from the anterior end of sternum (where it is 8 mm.) to hinder end (13 mm.). The margin of the last sternebra—or, rather, of each of the two constituent ossicles—is not rounded, but slopes away from the dorsal surface outwards and downwards, so that the lower surface is wider than the upper (43 mm.).
The hyoid bone is very briefly referred to by Wall, and is rather more fully described by Van Beneden and Gervais, who figure it. In the Purakanui specimen it was complete, the bones and cartilages being uninjured.
The basi-hyal is a flat irregularly semicircular bone, at the anterior margin of which is a pair of cartilages, which evidently correspond to the bony apex of the basi-hyal of Physeter, but which in Cogia do not appear to ossify. The thyro-hyal bones are circular discs imbedded in a large cartilaginous plate.
The anterior cornu consists of two segments, a proximal short, curved, subcylindrical cartilage (cerato-hyal) and a longer distal region, in the middle of which is a cylindrical bone (the stylo-hyal).
The two anterior cornua arise close to one another from the cartilages referred to as joining the anterior end of the basi-hyal.
Basi-hyal: Greatest breadth, 84 mm.;. greatest length, 66 mm.; thickness, 5 mm.; length of cartilaginous cap, 18 mm.; breadth, 20 mm.; length of ossification in thyro-hyal, 55 mm.; breadth, 46 mm.; length of each half of basi- and thyro-hyal from anterior end of cap to posterior end of cornu, 156 mm.; greatest width across external margins of posterior cornua, 188 mm.
Anterior cornu: Total length, 220mm.; cerato-hyal cartilage (along middle line), 37 mm.; stylo-hyal, 175 mm.; length of bone (along middle line), 65 mm.; thickness, 15 mm.; greatest length along hinder margin, 75 mm.
Skeleton of Fore Limb.—This has been but indistinctly figured by Von Haast, whose specimen was imperfect, and by Wall, but more accurately by Krefft. The scapula is a nearly equilateral triangle, the upper border being curved. The greater part of the outer surface (post-axial fossa) is feebly concave. The inner surface is nearly flat, but as the anterior border is slightly everted so as to form a low rounded but depressed ridge, extending nearly across the bone, and as the superior border is also somewhat everted, the inner face is slightly convex.
The spine is but feebly developed, but the acromion is a large compressed squarish process, obliquely truncated distally. It bears on its upper margin a shorter process.
The coracoid process is large and well marked, nearly as long as the acromion, but narrower. The glenoid cup is oval.
|Greatest height (measured from highest point of superior border to anterior margin of glenoid facet)||164|
|Length of posterior border||107|
|Length of anterior border||159|
|From antero-posterior angle to origin of acromion||76|
|Breadth, greatest (from anterior to posterior angle of superior border)||184|
|Breadth immediately above acromion||83|
|Breadth from posterior margin of glenoid to tip of acromion||101|
|Acromion: Vertical height, near root||35|
|From posterior margin of glenoid to end of coracoid||84|
|From anterior margin of glenoid to end of coracoid||47|
|Coracoid: Height at root||22|
|Glenoid facet: Length||46|
|Glenoid facet: Width||31|
The humerus is provided with a small deltoid crest 15 mm. long and 5 mm. in height. The head and tubercle are firmly united to the end of the shaft, as is also the distal epiphysis; but the epiphyses of the radius and ulna are not as yet united to these bones. Each of these epiphyses is still imbedded in a great mass of cartilage and is invisible in the preserved specimen; the bone can, however, be felt by probing the cartilage with a needle. The proximal epiphysial cartilage of the ulna is prolonged downwards to form a spur on the post-axial side of the limb, which in Physeter is represented by a bony olecranon. Possibly this becomes ossified in a fully matured animal, though it is not shown in Von Haast's drawings; but the photograph accompanying the second edition of Wall's paper and the woodcut in Krefft's just indicate a small process here.
The carpal bones are five in number, three in the proximal row and two in the distal. Each is an irregular circular disc of bone imbedded in cartilage, with vertical sides. The pisiform is cartilaginous. There is, too, a curious prolongation of the distal epiphysial cartilage of the radius, which extends outside the pre-axial carpal and touches the 1st meta-carpal.
In the fingers each phalanx is provided with its own epiphysial cartilage, but with no bony epiphysis, and the neighbouring cartilages are distinct, not fused as in Mystacocetes. The metacarpals are short, not much longer than the phalanges.
The 1st digit consists of a rounded metacarpal resembling a carpal. This is followed by a long phalanx and a shorter one. In the 2nd the metacarpal is broader than that of the other digits, but not so long as in the 3rd. This is followed by ten phalanges, of which the terminal is very small, and the three sub-terminals are circular. The 3rd has seven phalanges, the 4th six phalanges, and the 5th three phalanges, which are all nearly circular, as are the terminals of the other digits. On the left hand the 1st has two phalanges, rather larger than in the right; the 2nd has nine, the 3rd seven, the 4th six, and the 5th two only.
The lengths of the digits in ascending order are—I. shortest, V., IV., III., II. The following are the lengths of the digits: Right hand—The 1st measures 55 mm. along pre-axial border, and including cartilage; 2nd, 183 mm.; 3rd, 148 mm.; 4th, 102 mm.; 5th, 68 mm. The terminal cartilages are missing in the 2nd, 3rd, 4th, and 5th digits. Left hand—The 1st measures 52 mm.; 2nd, 185 mm.; 3rd, 158 mm.; 4th, 114 mm.; 5th, 52 mm.
The total length of limb from head of humerus-to tip of 2nd digit is 372 mm.
Humerus: Length (including cartilage), 95 mm.; bone only, 65 mm. Transverse diameter of bone—Upper end, 45 mm.; lower end, 50 mm. Thickness, 24 mm.
Radius: Length along pre-axial side, 75 mm.; post-axial, 60 mm. Length of bone only (along its middle), 60 mm. Least breadth (along its middle), 30 mm. Thickness, 12 mm.
Ulna: Total length along post-axial, 63 mm.; pre-axial, 60 mm. Total length bone (in middle), 55 mm. Least breadth, 26 mm. Thickness, 10 mm. Olecranon, 25 mm.
Total breadth at distal end of R.U. (including cartilage), 80 mm.
In the 2nd edition of Wall's paper a photograph of the right limb is given, which appears to agree well with the limb of the present specimen, although the bones of the former had to be pieced together, and were not found in situ, so that the cartilaginous parts do not exhibit that characteristic feature above referred to. Wall describes “seven” carpal bones, but it is pretty evident that the “two linear transverse bones” are the distal epiphyses of the radius and ulna, at the ends of which he locates them. The remaining five are accurately shown in the photograph and described in the text. It is a more accurate representation of affairs than the woodcut illustrating Krefft's paper. The figure also seems to show the peculiar prolongation of the cartilage from the radial epiphysis towards the metacarpal of the first digit. The pisiform, however, is not shown.
1. Van Beneden and Gervais. “Ostéographie des Cétacés,’ 1880, pp. 349 and 515, pls. 20 and 61.
2. Gray. Zoology of “Erebus” and “Terror,” 1846.
3. Von Haast. Trans. N.Z. Inst., vi., 1873, p. 97.
4. Krefft. P.Z.S., 1865, p. 708.
5. Owen. Trans. Zool. Soc., vi., 1865, pp. 30 and 171.
6. Wall. “Skeleton of New Sperm Whale (Euph. grayi).” Australian Museum, 1887 (2nd ed.).