ZIPHIUS CAVIROSTRIS Cuvier.
Ziphius cavirostris Cuvier, Oss. foss., 2d ed., vol. 5, 1823, p. 353. Hyperoödon gervaisii Duvernoy, Ann. Sci. Nat., ser. 3, Zoöl., vol. 5, 1851, p. 49. Ziphius gervaisii Fischer, Nouv. Arch. Mus. Paris, vol. 3, 1867, p. 55. Hyperoödon semi-junctus Cope, Proc. Acad. Nat. Sci. Phila., 1865, p. 15. Ziphius semijunctus True, Proc. U. S. Nat. Mus., vol. 8, 1886, p. 586. Ziphius grebnitzkii Stejneger, Proc. U. S. Nat. Mus., vol. 6, 1883, p. 77.
It has not seemed to me necessary in the present connection to attempt to cite all the multitudinous names which have been given to this species, especially as those zoologists most competent to judge, including Van Beneden, Flower, and Turner, after detailed consideration, have concluded that but one species of Ziphius, or at most two species, exist at present.[35]
Nearly all the skulls in European museums are assigned by the zoologists mentioned to Z. cavirostris proper, but some doubt has been entertained regarding two or three European skulls, and one specimen from Argentina, described by Burmeister. These last-mentioned specimens have been thought to possibly represent a second species, Z. gervaisii. The principal characters of the latter are the narrow, flat premaxillæ, the lack of a prominent mesirostral ossification, and small teeth. From the large series of skulls in the National Museum, I am able to dispose of the doubt concerning Z. gervaisii. I find that wherever the characters above mentioned occur the sex (when known) is female. There is every reason, therefore, to believe that Z. gervaisii is the female of Z. cavirostris.[36] I will return to this point again later.
In 1865 Cope described a species from Charleston, South Carolina, under the name of Hyperoödon semijunctus. In 1886 I referred it to the genus Ziphius, but was in doubt as to its specific identity. I thought that it might represent Z. gervaisii, which is interesting in the present connection because the type-specimen was a female.
In 1883 Dr. L. Stejneger described a species which he had discovered on Bering Island, Bering Sea, under the name of Z. grebnitzkii. Through the instrumentality of Doctor Stejneger and Governor Grebnitzki, the National Museum later received a large series of skulls from the same locality. The question of whether this species is identical with Z. cavirostris, or distinct, has caused me much study, and forms the principal subject of this chapter.
The National Museum has at present the following material, which may be considered as certainly representing Z. cavirostris:
1. A complete skeleton and cast of an adult female, 19 feet 4 inches long, obtained at Barnegat City, New Jersey, October 3, 1883. Cat. No. 20971.
2. A complete skeleton and photographs of an adult male, 20 feet 1 inch long, obtained at Newport, Rhode Island, in 1901, through Dr. E. A. Mearns, Mr. L. di Z. Mearns, and Capt. Gus Soderman. Cat. No. 49599.
3. The collection contains also the skeleton of the young female individual obtained at Charleston, South Carolina, prior to 1865, which constitutes the type of Hyperoödon semijunctus Cope. It was originally in the Charleston College Museum, but later was received by the National Museum in exchange. This individual was between 12 and 13 feet long. Cat. No. 21975.
In addition, the national collections contain the following material, known to, or supposed to, represent the species Z. grebnitzkii:
4. Cat. No. 20993. Skull of a male (?).[37] Collected by Dr. L. Stejneger in Bering Island, 1882. Orig. No. 1521. Type of Ziphius grebnitzkii.
5. Cat. No. 21245. Skull. Orig. No. 1758.
6. Cat. No. 21246. Skull. Orig. No. 2531.
7. Cat. No. 21247. Skull. Orig. No. 1849.
8. Cat. No. 21248. Skull of a male (?).
9. Cat. No. 83991. Skull.
The five skulls preceding were also collected by Doctor Stejneger in Bering Island in 1882 and 1883.
10. Cat. No. 22069. Skull of a female (?).[37]
11. Cat. No. 22874. Skull.
12. Cat. No. 22875. Bones of an immature individual.
These three specimens were collected and presented by N. Grebnitzki.
13. Cat. No. 142579. A series of photographs of an individual captured in Kiska Harbor, Alaska, September, 1904. Presented by Dr. J. Hobart Egbert.
14. Cat. No. 84906. Photograph of the skeleton of an individual washed ashore at St. Simon Island, Georgia, in 1893, and belonging to Mr. W. Arnold.
In the genus Ziphius, as in other ziphioid genera, a study of the characters of the skull appears to afford the best basis for discrimination of species. We have first to consider whether the North American species is the same as the European and New Zealand species, and afterwards whether the North Pacific species is identical with or distinct from these.
The published measurements of specimens from the coasts of Europe and New Zealand, currently believed to represent the single species Z. cavirostris, are rather meager, and, furthermore, prove, on examination, to present so little uniformity that they are of limited use for comparison with measurements of skulls from the Atlantic coast of the United States. About all that can be said is that the latter skulls are of about the same size as the former and that the proportions do not present any striking differences. For detailed measurements of the American skulls, see [page 53].
On account of the uncertainty as regards the measurements, I have had recourse to the published descriptions and figures, especially those of Van Beneden, Sir William Turner, and Doctor Haast. So far as I can perceive, there is nothing in these descriptions that is not applicable to the skulls Nos. 49599 and 20971, from Newport, Rhode Island, and Barnegat City, New Jersey, respectively, in the National Museum, and I can find no reason for regarding the latter other than as representatives of Z. cavirostris.
HISTORY OF THE NEWPORT, RHODE ISLAND, SPECIMEN.
Of the Newport specimen, No. 49599, the Museum has the complete skeleton, together with external measurements and a photograph. From data at hand it appears that the animal was originally obtained in Narragansett Bay about October 30, 1901, and afterwards towed to Fort Adams, near Newport. A few days later it was sent adrift again and stranded in the harbor of Dutch Island, near Canonicut Island, which is opposite Newport. While at Fort Adams its existence was made known to the Museum by Dr. E. A. Mearns, U. S. Army, and his son, Louis Mearns; and a preparator was sent to obtain the skeleton. With the aid of Captain Soderman, of the government tug Monroe, he found it at Dutch Island, and reported that it was a male, 20 feet 1 inch in length, measured along the curves of the back (18 feet 6 inches in a straight line). The epidermis was nearly all lacking, but the back appeared to have been black. The length in a straight line, as reported by Mr. Louis Mearns, was 19 feet. The complete measurements taken by the preparator, Mr. J. W. Scollick, are as follows:
External dimensions of Ziphius cavirostris, male, Cat. No. 49599, U.S.N.M., Newport, Rhode Island.
| Ft. | in. | |
|---|---|---|
| Total length, along curve of back | 20 | 1 |
| Total length, in straight line | 18 | 6 |
| Tip of snout to posterior margin of dorsal fin | 13 | 10 |
| Tip of snout to axilla | 5 | 2 |
| Tip of snout to eye | 2 | 5½ |
| Tip of snout to anterior margin of blowhole | 2 | 4 |
| Length of mouth | 1 | 1 |
| Breadth of blowhole | 0 | 5½ |
| Length of pectoral fin, from head of humerus to tip, straight | 2 | 2 |
| Vertical height of dorsal fin | 0 | 10 |
| Breadth of flukes, from tip to tip | 5 | 3 |
| Greatest girth (estimated) | 10 | 0 |
The breadth of the pectoral fin, as shown by the skeleton, was 5¾ inches.
The photograph, which is reproduced in [Pl. 41], fig. 4, gives a good idea of the general form of the animal.
HISTORY OF THE BARNEGAT CITY, NEW JERSEY, SPECIMEN.
Of the Barnegat City specimen, No. 20971, the Museum has the complete skeleton, together with a cast of one-half of the entire animal, and another of the head, and some measurements, all of which were obtained by Mr. William Palmer and myself October 3, 1883. The Museum received notice of the stranding of this specimen from Capt. J. H. Ridgway, of the United States life-saving station at Barnegat City. It was an adult female, 19 feet 4 inches long in a straight line. The complete measurements, taken in straight lines with a rod and cord, are as follows:
External dimensions of Ziphius cavirostris, female, Cat. No. 20971, U.S.N.M., Barnegat City, New Jersey.
(Measured in straight lines with rope and bar.)
| Ft. | in. | |
|---|---|---|
| Total length | 19 | 4 |
| Tip of snout to eyes | 2 | 1 |
| Tip of snout to blowhole | 2 | 0 |
| Tip of snout to anterior base of pectoral fin | 3 | 10½ |
| Tip of snout to anterior base of dorsal fin | 12 | 0 |
| Tip of snout to anterior angle of vent | 12 | 3½ |
| Tip of snout to corner of mouth | 11½ | |
| Length of anterior margin of pectoral fin | 2 | 1½ |
| Length along center of pectoral fin | 1 | 7 |
| Greatest breadth across pectoral fin | 6¾ | |
| Length of anterior margin of dorsal fin | 1 | 6 |
| Length of base of dorsal fin | 1 | 0 |
| Vertical height of dorsal fin | 1 | 0 |
| Breadth of flukes from tip to tip | 5 | 5 |
| Antero-posterior length of flukes | 1 | 7 |
| Length of eye | 2 | |
| Breadth of eye | 1 | |
| Girth around eyes | 3 | 1½ |
| Girth at anterior margin of dorsal fin | 7 | 0½ |
| Girth at root of pectoral fins | 6 | 0½ |
| Breadth of lower jaw at middle of length | 4½ | |
| Breadth of upper jaw at middle of length | 5 | |
| Breadth of blowhole | 5 | |
| Distance from posterior angle of eye to ear | 4½ |
I neglected to make a full description of the color, but noted that it was stone gray, lighter above and darker below; snout nearly white. The cast, which was painted from a sketch made at Barnegat City and from pieces of skin brought to Washington, bears out this note in general, but with modifications. The color of the body as a whole is gray tinged with dull yellowish. The gray is darker on the back than on the belly, but on the latter is a large area of dark brown, reaching from near the pectoral fins to and beyond the anus, and halfway up on the sides. On this dark area are several large oval whitish blotches, some two inches in diameter. Both upper and lower jaws nearly to the angle of the mouth are cream white. On the sides and belly the gray color is speckled with black spots of about the size of a grain of wheat. The pectoral fins are dark gray above and below; the flukes were similarly colored.
A comparison of the dimensions of the two specimens above described with those of European and New Zealand specimens is afforded by the following table (the measurements being reduced to percentages of the total length):
External dimensions of Ziphius cavirostris. (Reduced to percentages of the total length.)
Column Headings: A: Newport, Rhode Island 49599 U.S.N.M., male, 1901. B: Barnegat City, New Jersey, 20971 U.S.N.M., female, 1883. C: New Brighton, New Zealand, female. D: Punta, Corsica, 1842. E: Buenos Ayres, Argentina, male, 1865.
| Measurements. | Aa | Ab | Bb | C | D | E | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ft. | in. | Ft. | in. | Ft. | in. | Ft. | in. | Ft. | in. | Ft. | in. | |
| Total length | 20 | 1 | 18 | 6 | 19 | 4 | 19 | 6 | 19 | 0 | 12 | 11½ |
| Per cent. | Per cent. | Per cent. | Per cent. | Per cent. | Per cent. | |||||||
| Tip of snout to posterior margin of dorsal | 69.0 | 74.8 | 67.2 | [67.1] | [78.5] | [70.8] | ||||||
| Tip of snout to axilla | 25.3 | 28.0 | c20.0 | d24.4 | ... | c[25.0] | ||||||
| Tip of snout to eye | k12.2 | 13.3 | 10.8 | 12.8 | ... | 10.9 | ||||||
| Tip of snout to anterior end blowhole | 11.2 | 12.6 | 10.4 | ... | ... | 11.4 | ||||||
| Length of mouth | 5.4 | 5.9 | e 5.0 | 6.4 | ... | [ f] 5.3 | ||||||
| Breadth of blowhole | 2.3 | 2.5 | 2.2 | 2.6 | ... | 1.2 | ||||||
| Length of pectoral from head of humerus | 10.8 | 11.7 | ... | g12.8 | ... | ... | ||||||
| Length of pectoral from axilla | h7.5 | 8.1 | hi8.1 | ... | g 8.3 | 8.6 | ||||||
| Greatest breadth of pectoral fin | j2.4 | j2.6 | 2.9 | 3.0 | 2.9 | 3.0 | ||||||
| Vertical height of dorsal fin | 4.1 | 4.5 | 5.2 | 3.4 | 3.5 | 4.3 | ||||||
| Breadth of flukes, tip to tip fin | 26.1 | 28.4 | 28.0 | 31.2 | ... | 27.3 | ||||||
a Curvilinear. b Straight. c To anterior base. d Lower jaw to “beginning of pectoral.” e From tip of upper jaw. f From tip of lower jaw. g Points of measurements not specified. h From the bones; from outer anterior margin of proximal expansion of ulna. i Along center. j From the bones. The external measurement originally taken by Scollick is entirely too large. k The skull gives this measurement as 10.4 per cent. The original measurement by Scollick is entirely too large and can not be correct. The same is probably true regarding length to blowhole, but I can not prove it.
The close correspondence in proportions shown in this table favors the idea of specific identity, and taken with the similarity in size, and characters of the skull, warrants, I think, the assumption that the specimens from the Atlantic coast of the United States belong to Z. cavirostris.
COLORATION.
It should be remarked, however, that the Barnegat City specimen does not agree in color with any of the European or New Zealand specimens. On the other hand, the latter show a most extraordinary diversity in color, some being black, with the head and back as far as the dorsal fin white; others all black above, white below, and the head black and brown. The color of the young specimen from Buenos Ayres, Argentina, is described by Burmeister as follows:
All the body of the animal is of a light gray color, a little yellowish, resembling the color of light ash, but much darker on the back and much lighter on the belly. The fins are much darker than the back—almost black—and the large fin of the tail has a very pure white area of irregular shape on the underside.
If the indications from the skull and proportions are trustworthy Z. cavirostris must be a species in which the color is very variable, differing perhaps in the two sexes, or with differences in age. This is, however, by no means certain at present, and whether the diversities of color reported in different specimens are merely individual variations, or are due to post-mortem changes, remains to be discovered. It will be noticed that the color of the Argentine specimen is nearest to that of the Barnegat City specimen.
TYPE OF ZIPHIUS SEMIJUNCTUS (COPE).
The type-specimen of Ziphius semijunctus (Cope), as already mentioned, is a young female.[38] The most noticeable characters which it presents are that the premaxillæ are flat proximally, and that the teeth are small, sharp-pointed and open at the roots. The form of the teeth is undoubtedly due to immaturity, but as the shape of the premaxillæ is similar to that found in the nominal species gervaisii, it might be thought necessary to refer semijunctus to the latter species. As will be shown later, however, this form of the premaxillæ appears to be characteristic of the adult female of cavirostris, and of immature individuals of either sex, the young, as in many kinds of animals, resembling the adult female rather than the male.
I have been able to find but one character in the skull of semijunctus which might be regarded as specific. This is that the lachrymal bone is thick distally, and cut off square at the end. In other specimens of Ziphius examined it is thin and flat, and rounded or pointed at the end. As there is much individual variation in the form of the lachrymal, this peculiarity alone is, in my opinion, an insufficient indication of the validity of the species.
COMPARISON OF SKELETONS.
A comparison of the skeletons of the three individuals from the Atlantic coast of the United States reveals a number of differences of more or less importance. Were it not for the lack of reliable differences in the skulls, it might be considered that these variations in other parts of the skeletons indicated specific difference. I am disposed, however, since the Barnegat and Newport specimens are of opposite sexes, to regard them partly as sexual and partly as individual. In the case of the Charleston specimen (semijunctus), the skeleton, besides being immature, has been very much damaged by careless handling, and nearly all the bones are somewhat abraded. It is, therefore, only available to a limited extent for purposes of comparison. As no description of a Ziphius skeleton from the coast of the United States has, so far as I am aware, been published hitherto, and as descriptions of skeletons of Old World specimens are few and rather brief, I shall give below a detailed comparative description of the American specimens. For the sake of brevity, I shall refer to each specimen merely by the locality.
VERTEBRAL COLUMN AS A WHOLE.
The vertebral formula in the three North American specimens and in four Old World specimens and Burmeister’s Argentine specimen is as follows:
Vertebral formula of Ziphius cavirostris.
| Locality and sex. | C. | Th. | L. | Ca. | Total. |
|---|---|---|---|---|---|
| Newport, Rhode Island, male | 7 | 9 | 10 | 20 | 46 |
| Barnegat City, New Jersey, female | 7 | 9 | 11 | 18(+1?) | 46(?) |
| Charleston, South Carolina, female | 7 | 10 | 10 | 16(+3?) | 46(?) |
| Holma, Sweden (Malm) | 7 | 10 | 10 | 18(+1) | 46 |
| Pisa Museum (Van Beneden) | 7 | 9 | 11 | 16+ | 43+ |
| Warrington, New Zealand (Scott and Parker) | 7 | 10 | 9 | 20 | 46 |
| Lyttleton Harbor, New Zealand (Haast) | 7 | 9 | 11 | 19 | 46 |
| Buenos Ayres, Argentina (Burmeister), male | 7 | 10 | 10 | 22 | 49 |
In the figures of the Argentine specimen the last ten caudals are practically without characters, and it is perhaps allowable to question whether the terminal two or three were not added to make an even taper to the end of the column. If such be not the case, this specimen had more vertebræ than any other.
CHARACTERS OF THE VERTEBRÆ.
Newport (male).—The seventh cervical vertebra presents a conical metapophysis, which on the first thoracic vertebra forms of a rather thick, long, declining process ending in a facet for the tubercle of the first rib. This metapophysis maintains nearly the same form as far as the sixth thoracic vertebra, but on the third thoracic a mammiliform process makes its appearance on the anterior margin near the tip, and becomes more prominent on each succeeding vertebra. On the seventh thoracic it becomes larger, thin, and upright, and widely separated from the articular facet for the tubercle of the rib. On the centrum of this vertebra lower down is a second much larger rugose articular facet. On the eighth thoracic vertebra the upper articular process disappears altogether and is replaced by a transverse process on a lower level, with a facet at the free end for the rib. On the ninth thoracic the transverse processes are larger and nearly straight. They are longer on the first lumbar and incline a little forward. Those of the succeeding vertebræ are similar, but decrease gradually in length, while somewhat increasing in breadth. They are last traceable on the ninth caudal. On the eighth caudal they are perforated by a foramen.
All the vertebræ from the first cervical backward have neural spines as far as and including the eleventh caudal. The spine on the first thoracic is rather short, narrow and pointed. These spines increase in height in succeeding vertebræ as far as the sixth lumbar; at the same time the breadth increases antero-posteriorly and the tip becomes expanded. The spines are nearly equally high on all the succeeding lumbars, but begin to decrease on the caudals and disappear altogether on the eleventh caudal.
The anterior zygapophyses and metapophyses maintain a nearly constant position close to the top of the centra throughout the column, from the seventh thoracic backward, and are vertical, thin, and oblong, squared or rounded. They begin to decrease in size noticeably on the first caudal, and on the seventh caudal are mere swellings at the sides of the nearly horizontal plate from which the neural spine springs. They are traceable as far as the twelfth caudal.
A ridge appears on the side of the neural arch near its base on the fifth caudal and is stronger and very marked on those following, to the ninth caudal. A ridge unites the anterior and posterior facets for the chevrons on the ninth and succeeding caudals.
Barnegat City (female).—Unlike the Newport skeleton, there are no neural spines on the fifth, sixth, and seventh cervicals. The spine on the first thoracic vertebra is quite short and sharp, and on the second, third, and fourth thoracics also is rather pointed, though of increased length. There is no metapophysis on the seventh cervical.
On the seventh thoracic the facet for the tubercle of the rib, instead of being very prominent, becomes inconspicuous. The metapophysis is flat and squared, and there is no lower facet on the side of the centrum. On the eighth thoracic the metapophysis is thin, squared, and vertical, and a well-formed transverse process appears on the side of the centrum. The transverse processes of the ninth thoracic are a little curved backward, and on the first lumbar and succeeding vertebræ bent forward. These processes are less tapering on all the lumbars than in the Newport skeleton. They disappear on the eighth caudal. None is perforated.
The longest neural spine is on the sixth lumbar, and on all the lumbars both the anterior and posterior edges are somewhat convex. Hence their shape is rather different from those of the Newport skeleton, in which the anterior margins are somewhat concave. The tips of the spines are rather suddenly expanded. The spines of the caudals are rather more expanded at the tip and more inclined backward than in the Newport skeleton. They disappear on the eleventh caudal.
The horizontal plate joining the metapophyses is noticeable on the fifth caudal. The ridge on the side of the neural arch is first noticeable on the fourth caudal and is very strong on the fifth, sixth, and seventh. The metapophyses are last traceable on the twelfth caudal.
Charleston (female, jr.).—This skeleton resembles the Newport one as regards the facets for the articulation of the tubercles of the ribs, except that the seventh thoracic resembles the sixth and has no lower facet on the side of the centrum. The transverse processes of the ninth thoracic are rather strongly curved backward, while those on the last thoracic and first lumbar are nearly straight. On succeeding vertebræ they are inclined forward. They are last traceable on the eighth or ninth caudal (vertebra 35 or 36). None is perforated by a foramen.
Though the vertebræ are defective, there appear to have been no neural spines on the fourth to the seventh cervicals, inclusive. The spine on the first thoracic is short, and on the first to the fourth is pointed. The spine disappears on the tenth caudal (vertebra 37).
The metapophyses assume the vertical position on the eighth thoracic. The last of these processes is barely traceable on the tenth caudal (vertebra 37). The ridge on the side of the neural arch is well marked on the fifth to the ninth caudals, inclusive. On the seventh caudal (vertebra 34) the anterior and posterior facets for the chevrons are united on the right side, and on the eighth caudal and succeeding vertebræ on both sides.
CERVICAL VERTEBRÆ.
Barnegat City (female).—The first four cervicals are united. The foramen above the anterior articular facets of the atlas is complete, and the edges of these facets are raised. The inferior lateral process is flat, broad, and strongly bent backward.
Second cervical: Inferior lateral process nearly as long as that of the first cervical; broad, flat, and bent backward parallel with the process of the first cervical. Superior lateral process short, strong, and flat. A large incomplete foramen between it and the inferior process.
Third cervical: A short, conical inferior process, curved forward.
Fourth cervical: Similar, but with smaller and shorter inferior process. Neural arch and spine complete; the latter fused with the preceding spines. Arch not reducing the size of the neural canal.
Fifth cervical: Arch and spine broken. Arch nearly as broad as the anterior epiphysis of the centrum. Inferior lateral process short, straight, and directed obliquely outward.
Sixth cervical: Spine broken. Arch complete, nearly as wide as the anterior epiphysis. Inferior lateral process short, thick, knobbed, and directed obliquely outward and a very little forward. The left longer.
Seventh cervical: Spine obsolete. Arch complete, as wide as the anterior epiphysis. No superior lateral process or metapophysis. A thick articular facet for the head of the first rib on the middle of the side of the centrum. No inferior lateral process.
Fused spines of the first to fourth cervicals bent backward; the mass broad antero-posteriorly and rounded at the tip.
Newport (male).—First cervical with the foramen over the anterior articular facets incomplete, and the borders of the facets less raised. The facets also broader and more declined. Inferior lateral process thicker, somewhat tapering, and nearly transverse.
Second cervical: Inferior lateral process much shorter than that of first cervical, about parallel with it, but with the tip bent forward. Superior lateral process short, thick, and bent backward; joined to the inferior process on the right side, inclosing an oval foramen.
Third cervical: A short, straight, triangular superior process on the right side; that on the left short and blunt. Inferior lateral process long, thick, club-shaped, and curved backward.
Fourth cervical: Inferior lateral process similar to the last in shape, but shorter, broad and flat, and only slightly curved backward. Neural arch and spine separate from those of the third cervical; the arch rather smaller than those preceding it, and reducing the size of the neural canal.
Fused spines of the first to third cervicals nearly vertical, rather high, and obtusely pointed.
Fifth cervical: Spine pointed and quite long. Arch complete. Inferior lateral process short, squared, flattened, and directed outward obliquely.
Sixth cervical: Spine about as long as on the fifth cervical. Arch much narrower than the anterior epiphysis. Inferior lateral process prominent, thick, somewhat compressed, and directed downward.
Seventh cervical: Spine as high as the arch, obtusely pointed. Arch complete, as wide as the anterior epiphysis. A strong conical superior lateral process, or metapophysis, on a broad base, directed forward. An articular raised facet on the side of the centrum, directed obliquely backward. No inferior lateral process.
Charleston (female, jr.).—The first to fourth cervicals resemble those of the Newport skeleton, but the fourth entirely separate. All the lateral processes undeveloped, or broken off, except the right inferior lateral process of the atlas, which is like that of the Newport specimen. The anterior foramen of the atlas is incomplete, as in that specimen, and the spines of the conjoined vertebræ are vertical and pointed. ([Pl. 25], fig. 1.)
Fifth cervical: Spine wanting. Arch complete. Inferior lateral process undeveloped, or abraded.
Sixth cervical: Spine and processes broken. Arch wide.
Seventh cervical: Similar to that of the Newport skeleton, but the spine obsolete or broken.
THORACIC VERTEBRÆ.
Barnegat City (female).—First thoracic: Spine vertical, pointed, about as high as arch and centrum together. A moderately long process with articular facet for tubercle of rib on side of neural arch; facet elliptical and directed a little downward and forward. A smaller facet for head of second rib on posterior upper edge of centrum.
Seventh thoracic: Metapophyses long, extending horizontally, straight superiorly. A small articular facet on the outer side near the base, directed downward; strongest on right side. A very small facet on posterior upper edge of centrum, scarcely noticeable on right side. Neural spine rather narrow at tip; superior margin straight.
Eighth thoracic: Metapophyses squared and thin. A distinct transverse process on side of centrum about half as broad as the centrum is long, and as long as centrum is broad; flattened, squared, and a little curved backward and upward. Articular facet for rib elliptical and directed obliquely backward. A broad, shallow groove across base of transverse process, the anterior edge of which is emarginate proximally. Neural spine as in seventh thoracic.
Ninth thoracic: Metapophyses squared. Transverse process similar to that of eighth thoracic, but equal to centrum in length, little narrowed at base, and directed outward; anterior edge convex, posterior concave; articular facet occupying the posterior half of the distal edge. A very shallow groove proximally.
Newport (male).—First thoracic: Neural spine a little curved backward and rounded at tip; much higher than length of arch and centrum together. Articular facets as in Barnegat skeleton.
Seventh thoracic: Metapophyses similar in shape to those of Barnegat skeleton but with a very distinct facet on side of arch, terminating a process about as long as the greatest diameter of the facet; surface of facet rugose. Below this process, on side of centrum, a very large, oval, sessile facet, reaching forward nearly to the anterior face of the centrum and upward to its superior edge. A very low, small swelling on the posterior superior edge of centrum, probably indicating the point of attachment of a cartilage connecting the head of the eighth rib. Neural spine expanded at free end, and superior margin rounded.
Eighth thoracic: Metapophyses similar to those of Barnegat skeleton. A distinct transverse process nearly as broad as the length of the centrum, oblong or squared, flat, directed somewhat backward, but not upward. Articular facet for rib not occupying whole of free end and only slightly directed backward; anterior margin as in Barnegat skeleton. Neural spine similar to that of seventh thoracic.
Ninth thoracic: Similar to that of Barnegat skeleton, but transverse process longer than centrum and directed a little downward, articular facet occupying less than posterior half of free margin; proximal groove inconspicuous; anterior and posterior margins nearly straight.
Charleston (female, jr.).—The centra of the thoracic, as well as the lumbar, vertebræ in this individual present inferior median keels, and more or less concave sides, which is not the case in the Barnegat and Newport skeletons. This can not be due to immaturity, as in a still younger individual, supposed to represent Ziphius grebnitzkii, the thoracic vertebræ are rounded below. The neural spines of the thoracic vertebræ are much less inclined backward in semijunctus than in the Newport and Barnegat skeletons, but this is doubtless connected with age, as the younger series of vertebræ already mentioned exhibits the peculiarity in a more marked degree. A similar modification dependent upon age appears to affect Hyperöodon, as will be seen by comparing Van Beneden and Gervais’ figures in the Osteography, plate 18.
First thoracic: Similar to that of Newport skeleton, but spine not higher than arch alone. (A little abraded at tip, but probably undeveloped.)
Seventh thoracic: Metapophyses short (abraded), incompletely developed. A distinct facet on side of same on an elongated process, as in Newport skeleton, but no second larger one on side of centrum. No facet on superior margin of centrum either anteriorly or posteriorly.
Eighth thoracic: Transverse process similar to that of Barnegat skeleton, but anterior edge nearly straight; process about one-half as broad as length of centrum. (Indications of immaturity.)
LUMBAR VERTEBRÆ.
Barnegat City (female).—First lumbar: Similar to last thoracic, but transverse process expanded distally and slightly directed forward; a little longer than centrum; anterior and posterior edges emarginate proximally.
Eleventh lumbar (last): Centrum very long. Neural arch and spine very high, more than twice length of centrum. Spine inclined backward much beyond posterior face of centrum; anterior margin straight, posterior convex, tip expanded. Transverse process a little more than one-half length of centrum, somewhat expanded at distal end and curved forward so that tip is about in line with anterior face of centrum. Metapophyses close to centrum and to each other, semihexagonal in outline. A sharp median inferior ridge, and shallow posterior oblique channels on under side of centrum.
Newport (male).—First lumbar: Similar to that of Barnegat skeleton, but transverse processes considerably longer than the centrum and not expanded at tip; anterior edge straight, posterior only slightly emarginate proximally.
Tenth lumbar (last): Centrum like that in Barnegat skeleton. Neural arch and spine only slightly higher than length of centrum. Transverse process oblong, free margin nearly transverse; process inclined forward so that tip is a little beyond anterior face of centrum. Metapophyses close to centrum, rounded in outline. Neural spine much inclined backward; anterior edge concave, posterior convex, tip expanded. A rounded inferior median ridge and very distinct oblique posterior channels on under side of centrum.
Charleston (female, jr.).—First lumbar: Similar to that of Barnegat skeleton, but transverse process directed outward and scarcely or not at all forward; length of process equal to that of centrum; tip rounded (due to immaturity).
Tenth lumbar (last): Centrum very long. Neural arch and spine a little less in height than length of centrum. Transverse process oblong, curved forward, more than one-half as long as centrum. Metapophyses similar to those of Newport skeleton. Inferior median ridge very sharp; lateral channels rather indistinct.
CAUDAL VERTEBRÆ.
Barnegat City (female).—First caudal (vert. 28): Similar to last lumbar, but neural spine broader antero-posteriorly. Transverse process ࡪ length of centrum, inversely triangular, the tip much in advance of anterior face of centrum, free end somewhat rounded. Metapophyses similar to those of last lumbar. No median inferior ridge, but two short processes bearing facets for chevrons posteriorly and a very slight indication of similar process anteriorly, but without facets. Posterior inferior oblique channels indistinct.
Seventh caudal (vert. 34): Centrum (exclusive of chevron processes) nearly as deep as long. Neural arch and spine only a little higher than length of centrum, very much inclined backward and expanded at distal end; free border of spine straight. Metapophyses close to centrum, united nearly to tips by a horizontal plate. A ridge extends backward from their tips nearly across the arch. Another very prominent ridge traverses the centrum at the base of the arch. At the posterior end, a deep groove, convex forward, extends down the side of the centrum, making an emargination in the transverse process and proceeding thence down the lower side of centrum to its lower middle point, where it ends in a deep semicircular emargination between the anterior and posterior chevron facets. Transverse process a triangular stub, reaching nearly to the line of the anterior face of centrum. Chevron processes very large, and the median inferior surface of the centrum between them deeply grooved longitudinally.
Tenth caudal (vert. 37): Centrum as deep as long. Neural spine a low ridge, as long as the centrum, and extending beyond it posteriorly. No transverse processes. A foramen in side of centrum much above the middle and a similar one below. Close to the latter and below it another foramen pierces the ridge uniting the chevron processes, and appears below on side of longitudinal inferior median channel. Metapophyses small mammilliform processes on top of centrum.
Eleventh caudal (vert. 38): No processes. A very small neural spine. Posterior epiphysis strongly convex.
Twelfth caudal (vert. 39): A rounded mass without processes.
Thirteenth caudal (vert. 40): An oblong mass, with two grooves on each side, two widely separate foramina above and two closely approximated below, entering a common depression, with rounded projections on its borders.
Fourteenth caudal (vert. 41): Similar to thirteenth caudal, but with a single lateral groove.
Fifteenth caudal (vert. 42): Similar to fourteenth caudal, but sides extending upward and downward in a ridge. Inferior foramina nearly as far apart as superior and posterior epiphysis much smaller than anterior.
Sixteenth caudal (vert. 43): Similar to fifteenth caudal, but the disproportion of epiphyses greater and lateral ridges higher. Superior and inferior surfaces of centrum inclined.
Seventeenth caudal (vert. 44): Similar to preceding, but smaller.
Eighteenth caudal (vert. 45): Longer than high. Inferior ridge longer and larger than superior. Groove very large. Anterior face of centrum deeply concave, posterior flat. Posterior epiphysis very much smaller than anterior. Foramina very small, practically obliterated on right side.
Newport (male).—First caudal (vert. 27): Similar to last lumbar, but transverse process shorter, about two-thirds as long as centrum, oblong and but little constricted at base; distal margin nearly straight. The process does not extend forward quite to the line of the anterior face of centrum. No inferior median ridge, but strong posterior chevron processes. Postero-inferior oblique grooves very distinct.
Seventh caudal (vert. 33): Similar to the same vertebra in Barnegat skeleton, but neural spine more inclined backward and anterior border deeply concave. Metapophyses oblong, directed upward, not reaching anterior face of centrum as they do in Barnegat skeleton. Anterior face of centrum receding superiorly and the ridge opposite it on side of centrum shorter than in Barnegat skeleton. Ridge behind metapophyses indistinct. Postero-inferior oblique grooves as in Barnegat skeleton, but piercing transverse process, forming a foramen. Anterior and posterior chevron processes very large and receding very much, as do also the anterior and posterior faces of centrums.
Eleventh caudal (vert. 37): Similar to Barnegat skeleton, but spine shorter than centrum and not extending beyond it anteriorly or posteriorly. Metapophyses similar, but wider apart.
Twelfth caudal (vert. 38): Neural arch barely complete. No spine.
Thirteenth to nineteenth caudals (vert. 39-45): Similar to those of Barnegat skeleton.
Twentieth caudal (vert. 46): Rudely triangular, with a peg-like posterior projection, bearing the very small posterior epiphysis. No foramina. Anterior epiphysis deeply concave in middle.
Charleston (female, jr.).—First caudal (vert. 28): Similar to last lumbar, but only a faint inferior median ridge. Inferior outline of centrum antero-posteriorly very concave, which is not the case in the Barnegat and Newport skeletons. Posterior chevron processes prominent. Postero-inferior oblique grooves shallow.
Seventh caudal (vert. 34): Like the Newport skeleton. The transverse process not pierced or emarginate. Postero-inferior oblique grooves indistinct. Ridges on centrum very distinct. Right anterior and posterior chevron processes united and pierced by a foramen.
Tenth caudal (vert. 37): Similar to the same vertebra in Newport skeleton, but neural spine very short.
CHEVRONS.
The number of chevrons in the North American and some other specimens is as follows:
| Newport, Rhode Island. | 11 |
| Barnegat City, New Jersey. | 8(+3?) |
| Charleston, South Carolina. | 8+ |
| Buenos Ayres, Argentina (Burmeister). | 11 |
| Holma, Sweden (Malm). | 9 |
| Littleton Harbor, New Zealand (Haast). | 10 |
| Warrington, New Zealand (Scott and Parker). | 9 |
| Pisa Museum (Van Beneden). | 9 |
The chevrons are similar in form in the three North American specimens, with some differences which will be pointed out below.
Newport (male).—The first chevron consists of a pair of bones which are not united. They are longer than deep, their depth indeed being less than that of any one of the succeeding bones except the tenth and eleventh. Each presents one strong superior articulating facet. Second chevron, elongated antero-posteriorly, but not much deeper than the first. Third chevron very deep and only equaled in that respect by the fourth; narrowed and rounded off below. Fourth chevron largest and broadest (antero-posteriorly) of the series; expanded below and the lower border transverse. Fifth to eighth similar in form, but less deep successively, and the lower border more rounded. Ninth similar to eighth, but smaller and thinner. Tenth similar to first, longer (antero-posteriorly) than deep. Eleventh similar to tenth in form, but smaller.
Barnegat City (female).—First chevron bone lacking. Second like that of Newport skeleton, but smaller. Third similar to second, but much larger and more produced posteriorly; quite unlike the third in the Newport skeleton in form, and much less deep. Fourth, largest and deepest of the series; anterior and posterior borders rounded, and the inferior border similar. Fifth to eighth similar in form, but successively less deep, and all more expanded below; inferior border nearly straight. Ninth similar to eighth, but depth not exceeding breadth; lower angles produced.
Charleston (female, jr.).—The chevrons of this specimen resemble those of the Newport skeleton, but on account of immaturity they are all more or less rounded. The two sides of the first chevron are united. The second is without the posterior angular projection seen in the other specimens. The third is the deepest of the series. The eighth is not deeper than long, and hence resembles the tenth chevron of the Newport skeleton in proportion, but is, of course, much smaller. Two or three chevrons are lacking from the posterior end of the series.
RIBS.
Barnegat City (female).—First rib shortest and broadest, but considerably broader at proximal end than at distal end. Head and tubercle close together. The succeeding ribs increase in length and decrease in breadth to the fifth or sixth. The third, fourth, and fifth are expanded and flattened at distal end. Seventh, eighth, and ninth successively shorter. Distance between head and tubercle greater on second rib than on first, and on third is greater than on second. On the third to sixth, inclusive, the distance is about equal. The tubercle is scarcely distinguishable on the seventh rib, while on the eighth and ninth it is lacking, these ribs joining the transverse processes by a terminal facet only.
Newport (male).—Similar to those of the Barnegat skeleton, but first rib maintains nearly the same breadth throughout. Neck thicker than in Barnegat skeleton. Seventh rib terminates proximally in a single large rugose facet, which connects with a similar facet on side of centrum of seventh thoracic vertebra.
Charleston (female, jr.).—Similar to those of the Barnegat skeleton, but a distinct tubercle on the seventh rib. Eighth and ninth ribs end proximally in a transverse facet only, which is largest on the eighth. Tenth rib (represented by a fragment) only half as broad as the preceding ones and more nearly round in section.
STERNUM.
Barnegat City (female).—Five segments. Manubrium wider than long, convex inferiorly. Deep anterior and posterior notches, about equal, the former with an angular projection on each side. Facet for cartilaginous sternal rib thick and prominent. Second segment wider than long, about equally notched anteriorly and posteriorly, the two sides anchylosed together by a bony bridge, about as wide as the notches are deep. Third and fourth segments similar to second but smaller; similarly notched; left portion a little longer than right. Fifth segment elongated, left side very much so; the two sides joined by a narrow bridge; posterior notch very deep.
Newport (male).—Similar to sternum of Barnegat skeleton, but manubrium scarcely wider than long; posterior notch much longer than anterior, with parallel sides. Second and third segments similar to those of Barnegat skeleton but sides of latter not completely anchylosed together. Fourth segment in two pieces, with a wide interval between. Fifth segment triangular with deep anterior, triangular notch, a narrow bridge, and short posterior prolongation (the left longer than the right).
Charleston (female, jr.).—Resembles the sternum of the Barnegat skeleton rather than that of Newport skeleton, but anterior parts cartilaginous. Opposite sides of second, third, and fifth segments anchylosed together and those of fourth segment nearly so. ([Pl. 25], fig. 2).
SCAPULA.
Barnegat City (female).—Superior border irregular. Posterior angle acute. Anterior and posterior borders nearly straight. Ridges distinct. Acromion broad both at base and at tip, sharply bent upward, so as to be parallel with anterior border of scapula. Coracoid nearly as long as acromion, slender, a little curved upward, irregular and somewhat expanded at the end.
Newport (male).—Superior border irregularly rounded. Posterior angle obtuse, anterior angle projecting. Ridges indistinct. Anterior and posterior borders nearly straight, but irregular. Acromion broad at base, tapering toward the tip, which is again somewhat expanded; bent upward, but not sufficiently to be parallel with anterior margin of blade. Coracoid rather thick, irregular, strongly expanded at tip.
Charleston (female, jr.).—Rather too much abraded for comparisons, but posterior margin more concave than in either of the other skeletons.
FORE LIMB.
Barnegat City (female).—Fore limb much shorter than in the Newport skeleton. Humerus: Head quite oblique, the lower edge overhanging the shaft considerably on the ulnar side. Tuberosity level with upper surface of head, elliptical in outline when viewed from above. Deltoid ridge moderately prominent, irregular, rugose, and extending to about the middle of the shaft. Distal end of humerus not expanded. Bicipital groove inconspicuous.
Radius: Almost perfectly straight, but a little inclined toward ulna at oblique proximal end; scarcely expanded at distal end, which is lower externally than internally.
Ulna: Much slenderer than radius, rounded triangular in section, not expanded at distal end, where the margin is lowest externally. Olecranon well developed, thin, and pointed proximally.
Carpals: Five; two on ulna side, two median and one on radial side in line with first metacarpal. The proximal middle bone (intermedium) extends much farther proximally than those on each side of it.
Metacarpals: Metacarpal III longest, metacarpal II broadest. Metacarpal I oblong, or rather conical, with a lateral enlargement, and situated in line with the distal row of carpals.
Digits: First phalange of first digit short and conical.
Newport (male).—Fore limb considerably longer and more massive than that of the Barnegat skeleton but similar otherwise, except as follows:
Humerus: Head rather larger and less inclined. Deltoid ridge more prominent.
Radius: Broader proximally and rounded at distal end, where it extends outward beyond the carpal bones.
Ulna: Thicker, and olecranon less pointed.
Carpal bones: Middle carpal bone not extending farther proximally than those on either side of it.
Metacarpals: Metacarpal I nearly square, third longest, second to fourth more constricted.
Digits: First phalange of first digit long and cylindrical. Phalangeal formula: I, 1; II, 6; III, 6; IV, 4; V, 2.
Measurements of the skeletons above described are as follows:
Dimensions of four skeletons of Ziphius cavirostris.
Column headings: A: Barnegat City, New Jersey. 20971 U.S.N.M. female, adult. B: Newport, Rhode Island. 49599 U.S.N.M. male, adult. C: Charleston, South Carolina. 21975 U.S.N.M. female, young. D: Bering Island. (Vertebræ) young.
| Measurements. | A | B | C | D |
|---|---|---|---|---|
| mm. | mm. | mm. | mm. | |
| Length of skull | 945 | 915 | 797 | ... |
| First to fourth cervicals (vert. 1-4): | ||||
| Length of combined centra | 81 | 79 | 66 | 55 |
| Greatest breadth of atlas | 283 | 259 | 210(?) | 146 |
| Greatest height of atlas | 215 | 218 | 170 | 148 |
| First thoracic vertebra (vert. 8): | ||||
| Greatest breadth | 211 | 220 | 174(?) | 122 |
| Greatest heighta | 267 | 321 | 163 | 133 |
| Length of centrum | 42 | 46 | 32 | 19 |
| Height of centrum | 70 | 67 | 48 | 49 |
| Seventh thoracic vertebra (vert. 14): | ||||
| Greatest breadth | 142 | 158 | 147 | 128 |
| Greatest height | 440 | 417 | 260 | 182 |
| Length of centrum | 102 | 103 | 74 | 51 |
| Height of centrum (ant.) | 68 | 69 | 49 | 44 |
| Eighth thoracic vertebra (vert. 15): | ||||
| Greatest breadth | 253 | 288 | 177 | 100 |
| Greatest height | 447 | 427 | 265 | 186 |
| Length of centrum | 110 | 109 | 78 | 54 |
| Height of centrum | 65 | 69 | 51 | 47 |
| Ninth thoracic vertebra (vert. 16): | ||||
| Greatest breadth | 329 | 366 | 248(?) | 122 |
| Greatest height | 418 | 431 | 277 | 192 |
| Length of centrum | 117 | 117 | 82 | 58 |
| Height of centrum | 69 | 75 | 53 | 49 |
| First lumbar vertebra (vert. 17): | ||||
| Greatest breadth | 385 | 393 | b275 | 142 |
| Greatest height | 464 | 451 | b293 | 200 |
| Length of centrum | 122 | 120 | b89 | 62 |
| Height of centrum | 74 | 81 | b55 | 50 |
| Tenth lumbar vertebra (vert. 26): | ||||
| Greatest breadth | 362 | 335 | c230 | 158 |
| Greatest height | 524 | 488 | c343 | 242 |
| Length of centrum | 172 | 162 | c129 | 85 |
| Height of centrum | 107 | 109 | c78 | 71 |
| First caudal vertebra (vert. 27): | ||||
| Greatest breadth | 336(?) | d313 | 223 | 166 |
| Greatest height | 483 | d458 | 307 | 235 |
| Length of centrum | 178 | d160 | 127 | 91 |
| Height of centrum | 113 | d109 | 81 | 75 |
| Seventh caudal vertebra (vert. 33): | ||||
| Greatest breadth | 164 | e161 | 113 | 110 |
| Greatest height | f255 | f250 | 155 | f135 |
| Length of centrum | 139 | 131 | 103 | 77 |
| Height of centrum (ant.) | f111 | f119 | f85 | f78 |
| Twelfth caudal vertebra (vert. 38): | ||||
| Greatest breadth | 90 | g88 | 61 | 62 |
| Greatest height | 83 | g78 | 53 | 61 |
| Length of centrum | 55 | g56 | 46 | 47 |
| Fifteenth caudal vertebra (vert. 41): | ||||
| Greatest breadth | 64 | h62 | 49 | 45 |
| Greatest height | 54 | h52 | 33 | 30 |
| Length of centrum | 42 | h39 | 30 | 28 |
| Eighteenth caudal vertebra (vert. 45): | ||||
| Greatest breadth | 37 | i38 | ... | ... |
| Greatest height | 20 | i19 | ... | ... |
| Length of centrum | 24 | i22 | ... | ... |
| Twentieth caudal vertebra (vert. 46): | ||||
| Greatest breadth | ... | j25 | ... | ... |
| Greatest height | ... | j13 | ... | ... |
| Length of centrum | ... | j19 | ... | ... |
| Chevrons: | ||||
| Antero-posterior length of first chevron | ... | 74 | ... | ... |
| Depth of same | ... | 66 | 44 | ... |
| Length of second chevron | 83 | 107 | 55 | 38 |
| Depth of same | 87 | 85 | 74 | 63 |
| Length of third chevron | 114 | 91 | 61 | 46 |
| Depth of same | 135 | 206 | 123 | 90 |
| Length of fourth chevron | 125 | 122 | 67 | 51 |
| Depth of same | 213 | 206 | 111 | 67 |
| Length of eighth chevron | 80 | 86 | 43 | 35 |
| Depth of same | 108 | 115 | 41 | 33 |
| Length of ninth chevron | 84 | 74 | ... | 27 |
| Depth of same | 83 | 88 | ... | 19 |
| Scapula: | ||||
| Greatest length | 385 | 415 | k224 | 159 |
| Greatest height | 275 | 300 | 175 | 132 |
| Length of acromion | l115 | 159 | ... | 48 |
| Length of coracoid from edge of glenoid | 127 | 148 | 60 | 38 |
| Pectoral limb: | ||||
| Total length | 588 | 652 | ... | ... |
| Humerus: | ||||
| Length | 168 | 177 | 130 | 95 |
| Breadth at distal end | 69 | 69 | 52 | 42 |
| Radius: | ||||
| Length | m178 | m175 | m135 | ... |
| Breadth at distal end | 55 | 65 | 41 | ... |
| Ulna: | ||||
| Length without olecranon | 165 | 171 | 118 | ... |
| Length including olecranon | 220 | 225 | 150 | ... |
| Breadth at distal end | 44 | 42 | 30 | ... |
| Metacarpals: | ||||
| Length of first | 31 | 28 | ||
| Length of second | 52 | 55 | ||
| Length of third | 52 | 58 | ||
| Length of fourth | 44 | 51 | ||
| Length of fifth | 37 | 39 | ||
| Phalanges: | ||||
| Length of first phalange of first digit | 27 | 44 | ||
| Sternum: | ||||
| Total length | n803 | 821 | o550 | o395 |
| Length of manubrium | 259 | 306 | o203 | 105 |
| Breadth of manubrium | 286 | 333 | 193 | 128 |
| Length of fifth segment | o170 | p184 | o128 | p92 |
| Breadth of fifth segment | 133 | 168 | 86 | 82 |
| Ribs: | ||||
| Length of first rib (straight) | 405 | 410 | 277 | 191 |
| Breadth of first rib at proximal end | 88 | 110 | 65 | 46 |
| Breadth of first rib at distal end | 63 | 80 | 40 | 30 |
| Length of fifth rib (straight) | 785 | 770 | 545 | 415 |
| Length of ninth rib (straight) | 620 | 620 | ||
a The measurements of height of vertebræ are from center of inf. margin of centrum to center of tip of spine, unless otherwise specified. b Last thoracic. c Ninth lumbar. d Second caudal = vert. 28. e Eighth caudal = vert. 34. f Without chevron facet. g Thirteenth caudal = vert. 39. h Sixteenth caudal = vert. 42. i Nineteenth caudal = vert. 45. j Vert. 46. k Edges abraded. l A little broken. m In median line. n Without cartilages. o With cartilages. p Left side.
PHALANGEAL FORMULA.
The formulas for the ossified phalanges in two American[39] and three Old World specimens are as follows:
Phalangeal formula of five specimens of Ziphius cavirostris.
| Locality. | I. | II. | III. | IV. | V. |
|---|---|---|---|---|---|
| Newport, Rhode Island | 1 | 6 | 6 | 4 | 2 |
| Barnegat City, New Jersey | 1 | 6 | 6 | 4 | 3 |
| Villefranche, France (Haeckel) | 1 | 5 | 6 | 4 | 2 |
| Pisa Museum, Italy (Van Beneden) | 1 | 3(?) | 5 | 4 | 1 |
| Warrington, New Zealand (Scott and Parker) | 1 | 5 | 5 | 4 | 2 |
SUMMARY OF DIFFERENCES IN SKELETONS.
The chief differences between the Barnegat City and Newport skeletons are in the size and form of the processes of the cervical vertebræ, the form of the seventh and eighth thoracic vertebræ and of the ribs connected with them, the direction of the acromion of the scapula, the shape of the first phalange of the first digit, and of the posterior segments of the sternum. As far as the processes of the cervicals are concerned, these are known to be extremely variable in all cetaceans. The seventh and eighth thoracic vertebræ are those on which the mode of attachment of the ribs changes in ziphioid whales, and I have observed in the genus Mesoplodon, as here, that the processes and articular facets were very variable, being sometimes quite unlike on the two sides of the same vertebra. The direction of the acromion is probably subject to large individual variations, though this can not be determined at present, and the same is true of the form of the first phalange of the first digit. The form of the sternum is quite variable in all cetaceans, and can not be relied on for specific characters, without comparison of many individuals.
On the whole, I am of the opinion, as already stated, that we are not compelled by the differences noted to regard the Barnegat and Newport skeletons as representing different species. The Charleston skeleton is too young and imperfect to admit of serious consideration. The idea that the differences between the adult skeletons are probably individual receives support from the fact that the skeleton shown in the photograph from St. Simon Island, Georgia, mentioned on [page 31], No. 14, appears to possess a combination of characters exhibited by the other two.
AGE VARIATIONS IN SKULLS.
The series of skulls of Z. grebnitzkii, which the Museum owes to the activities of Dr. L. Stejneger and Mr. N. Grebnitzki, comprises specimens of different ages, and, as will be shown presently, probably both sexes. Taken together with the skulls from the east coast of the United States they probably represent very fully the variations which the skull undergoes in the present species. These changes may, perhaps, be best made evident by the following brief descriptions of the various skulls:
21975. Charleston, South Carolina.—Young female. (Type of Z. semijunctus.) All sutures open, and elements of occipital bone distinguishable. No mesethmoid ossification. Opposite maxillary notches, premaxillæ closely approximated, nearly flat and horizontal, and about level with adjacent parts of maxillæ. Left premaxilla grooved longitudinally at this point. Orifice of anterior nares on a level with lower end of rectangular projecting boss formed by superior portion of nasals. Rostrum pointed, much broader distally than it is deep. A very distinct rudimentary alveolar groove in distal end of each maxilla. Proximal end of vomer resting against anterior face of nasals and reaching up to overhanging boss. Anterior face of the latter nearly flat. ([Pl. 14], fig. 1; [pl. 18], fig. 1; [pl. 20], fig. 1; [pl. 21], fig. 2.)
Rami of mandible not anchylosed together at symphysis. Teeth hollow, open at the root, acute at apex, tipped with enamel; diameter 10 mm. ([Pl. 22], fig. 1; [pl. 24], fig. 1.)
20971. Barnegat City, New Jersey.—Adult female. Majority of sutures open, but those on superior surface of rostrum between maxillæ and premaxillæ partly anchylosed. Vomer nearly all anchylosed to rostral portion of premaxillæ; it presents a slight median elevation, but there is no mesirostral ossification. Right premaxilla in front of nares broad, flat, and horizontal; left, nearly so, but with a quite broad longitudinal groove. Opposite maxillary notches premaxillæ nearly on a level with adjacent parts. Orifice of anterior nares level with lower end of nasal boss. End of rostrum quite acute, and broader than deep. Rudimentary alveolar groove distinct distally. Proximal end of vomer anchylosed with anterior face of nasals and reaching up to nasal boss, which has a sharp median ridge completing nasal septum superiorly. Anterior face of nasal boss slightly concave on each side of median line. ([Pl. 14], fig. 2; [pl. 18], fig. 2; [pl. 20], fig. 2; [pl. 21], fig. 3.)
Rami of mandible anchylosed together at symphysis and suture largely obliterated. Teeth slender, cylindrical, rugose, rather blunt; roots closed; diameter 13 mm. ([Pl. 24], fig. 3.)
22069. Bering Island.—Adult female? All the sutures about as in preceding specimen. Mesirostral ossification distinct, rounded, extending from base of rostrum nearly to apex, but disappearing before reaching line of anterior ends of maxillæ. Its upper surface below that of premaxillæ. Premaxillæ approximated, and right premaxilla with an angular process near base of rostrum overlapping mesirostral ossification. Premaxillæ at base of rostrum, anterior nares, proximal end of vomer, and nasals as in preceding skull. Apex of rostrum moderately acute, broader than deep. Rudimentary alveolar groove shallow. ([Pl. 15], fig. 1.)
Rami of mandible anchylosed together and suture largely obliterated. Teeth somewhat fusiform, blunt; roots closed; diameter, 14 mm. ([Pl. 22], fig. 3.)
83991. Bering Island.—Similar in all respects to preceding, but mesirostral ossification a little less well developed.
22874. Bering Island.—Entirely similar to two preceding, but premaxillæ a little curved out from mesirostral ossification and left premaxilla opposite maxillary notch rather strongly inclined, nearly vertical. Anterior face of nasal boss distinctly concave. (Skull defective.)
21246. Bering Island.—Sutures as in three preceding skulls. Mesirostral ossification distinct and rounded, but much below level of premaxillæ. Rostral portion of premaxillæ narrow and widely divergent toward base of rostrum, leaving mesirostral entirely exposed. Right premaxilla on a line with maxillary notches strongly concave and sunk below level of maxillæ. Left premaxilla vertical, with a broad groove. Right premaxilla remains low and concave proximally, the posterior end being then abruptly turned upward and reaching level of vertex. Orifice of anterior nares on a level with lower end of nasal boss, and vomer resting against anterior face of nasals, which latter have a median ridge continuing nasal septum, but with a slight vacuity between the two. Rudimentary alveolar groove nearly obliterated. Outer sides of premaxillæ at distal end strongly concave. Rostrum rather acute, about as deep as wide opposite distal ends of maxillæ. ([Pl. 15], fig. 2.)
20993. Bering Island.—Adult male? (Type of Z. grebnitzkii). Majority of sutures open, but maxillæ and premaxillæ anchylosed together above and on the sides. Premaxillæ approximated anteriorly, but diverging posteriorly. Mesirostral ossification well developed, reaching level of premaxillæ; anteriorly rather narrow but a little broader near middle of rostrum, where it is beveled off abruptly. Behind this point premaxillæ strongly concave, nearly vertical and widely separated, forming a large and deep basin, in the bottom of which the vomer appears as a broad, irregular bony surface. Bottom of basin much below level of surrounding parts. Orifice of anterior nares much below level of nasal boss. Vomer reaching lower end of nasals. Anterior face of latter strongly concave, with only a moderate median ridge completing nasal septum above. Mesirostral with a median groove at distal end. Premaxillæ high at distal end, but sides nearly plane. Rostrum compressed near apex, deeper than wide. ([Pl. 16], fig. 1; [pl. 19], fig. 1; [pl. 20], fig. 3.)
Rami of mandible anchylosed together and suture partly obliterated. Teeth conical, with rather short, acute tips; roots closed, short and conical; diameter, 25 mm. ([Pl. 23], fig. 1; [pl. 24], fig. 2.)
21245. Bering Island.—Nearly all sutures between maxillæ and premaxillæ at end of rostrum, above and below, anchylosed together, but majority of others traceable. Condition of superior surface of skull very similar to that of preceding, but premaxillæ rather low at distal end. Mesirostral at distal end rather lower than premaxillæ and concave superiorly; more posteriorly assuming form of a narrow ridge, with a deep channel between it and premaxillæ on each side. More posteriorly still it widens rapidly, with a convex surface, and terminates abruptly with a truncated end, the surface of which is concave. A deep basin around nares, as in preceding skull. Orifice of anterior nares far below level of nasal boss. The latter largely absorbed and deeply undercut and concave in front. Nasal septum terminating before reaching lower end of nasals, and ridge on latter low and traversing left nasal. Sides of premaxillæ at distal end very concave. Rudimentary alveolar groove nearly obsolete. Rostrum blunt at apex, and about as deep as wide at anterior ends of maxillæ. ([Pl. 16], fig. 2.)
21248. Bering Island.—Similar to preceding, but mesirostral ossification higher than premaxillæ at distal end and convex above; less abruptly widened posteriorly and posterior termination flat. Narrow, deep grooves between ossification and premaxillæ on each side, or, in other words, premaxillæ more closely approximated to sides of mesirostral distally. Basin around nares and conformation of the several bones bordering it similar to preceding. Sides of premaxillæ concave at distal end, the grooves thus formed in them intruding some what on the maxillæ, especially posteriorly. Apex of rostrum very blunt, rounded off below and projecting above; deeper than wide. Rudimentary alveolar groove nearly obsolete. ([Pl. 17], fig. 1; [pl. 22], fig. 4.)
Rami of mandible anchylosed together and the symphysis and suture largely obliterated. Teeth very broadly fusiform; tip short and rather blunt; roots closed; diameter 30 mm.
49599. Newport, Rhode Island.—Adult male. All sutures on superior surface of skull more or less anchylosed together. Mesirostral ossification and premaxillæ all on one level near apex of rostrum, but at extreme tip mesirostral lower, forming a narrow ridge with a deep groove on each side between it and premaxillæ. The same conformation repeated more posteriorly, but grooves deeper and wider, while mesirostral maintains the same level as premaxillæ. It widens suddenly here, forming a broad flat-topped mass, which is a little overlapped by the premaxillæ. The mass terminates suddenly somewhat behind middle of rostrum with a deep concavity placed obliquely. Basin in front of the nares and conformation of bones composing it as in two preceding skulls. Vomer at proximal end touching lower end of nasals, and nasal septum continued behind and above it as a low ridge, composed of the inner edges of the two nasal bones and reaching up to the nasal boss. Outer sides of premaxillæ near distal end deeply concave. Apex of rostrum rather blunt, deeper than wide opposite distal ends of maxillæ; all the bones anchylosed together, but some of the sutures indicated by grooves. Rudimentary alveolar groove nearly obsolete. ([Pl. 17], fig. 2; [pl. 19], fig. 2; [pl. 21], figs. 1, 5.)
Rami of mandible anchylosed together at symphysis, the suture indicated only by a groove. Teeth large, broadly conical and tapering at the tip. Root very short, rugose, conical and closed; diameter 29 mm. ([Pl. 22], fig. 2; [pl. 23], figs. 2, 3.)
The dimensions of the several skulls are as follows:
Dimensions of ten skulls of Ziphius cavirostris (including the types of Z. grebnitzkii Stejneger and Z. semijunctus Cope).
Column headings: A: 83991. Bering Island. grebnitzkii. B: 21248. Bering Island. grebnitzkii. C: 22874. Bering Island. grebnitzkii. D: 21246. Bering Island. grebnitzkii. E: 20993. Bering Island. Type grebnitzkii. F: 22069. Bering Island. grebnitzkii. G: 21245. Bering Island. grebnitzkii. H: 21975. Type semijunctus. I: 20971. Barnegat, N. J. Female, cavirostris. J: 49599. Newport, R. I. Male, cavirostris.
| Measurements. | A | B | C | D | E | F | G | H | I | J |
|---|---|---|---|---|---|---|---|---|---|---|
| mm. | mm. | mm. | mm. | mm. | mm. | mm. | mm. | mm. | mm. | |
| Total length | 900 | 877 | a807 | 850 | 963 | 882 | 855 | 797 | 945 | 915 |
| Length of rostrum | 491 | 480 | a397 | 470 | 550 | 480 | 476 | 463 | 550 | 514 |
| Height from vertex to inferior border of pterygoids | 433 | 450 | ... | ... | 515 | 471 | 481 | 349 | 440 | 465 |
| Distance from tip of rostrum to posterior free margin of pterygoids (median) | 664 | 670 | ... | ... | 735 | 682 | 673 | 614 | 735 | 726 |
| Distance from the same to anterior end of nasals | 617 | 621 | a538 | 600 | 690 | 623 | 589 | 590 | 708 | 676 |
| Breadth between centers of orbits | 495 | 513 | b499 | 488 | 563 | b486 | 492 | 393 | 476 | 530 |
| Breadth between zygomatic processes | 511 | 513 | ... | 505 | 573 | 531 | 530 | 415 | 503 | 548 |
| Breadth between temporal fossæ | 270 | 309 | 325 | 300 | 349 | 317 | 311 | 242 | 302 | 313 |
| Breadth of rostrum at base | 319 | 331 | 345 | 324 | 380 | 337 | 320 | 249 | 307 | 337 |
| Breadth of rostrum at middle | 102 | 117 | b94± | 107 | 120 | 109 | 112 | 83 | 112 | 113 |
| Breadth of premaxillæ at same point | 54 | 67 | 58 | 62 | 78 | 70 | 75 | 44 | 62 | 80 |
| Depth of rostrum at middle | 66 | 81 | 80 | 79 | 118 | 117 | 113 | 50 | 77 | 107 |
| Breadth of premaxillæ in front of nares | 176 | 177 | 184 | 205 | 221 | 230 | 219 | 128 | 176 | 234 |
| Greatest breadth of anterior naresc | 74 | 77 | 77 | 90 | 98 | 103 | 108 | 70 | 76 | 112 |
| Greatest length of temporal fossa | 161 | 158 | 154 | 149 | 152 | 140 | 146 | 133 | 143 | 155 |
| Greatest depth of temporal fossa | 81 | 73 | 77 | 79 | 87 | 74 | 89 | 67 | 80 | 76 |
| Length of orbit (ant.-post.) | 131 | 133 | 132 | 130 | 137 | 126 | 117 | 113 | 134 | 132 |
| Distance from anterior end of orbit to maxillary notch | 78 | 92 | 82 | 70 | 83 | 89 | 85 | 61 | 82 | 99 |
| Length of tympanic bulla | ... | ... | ... | ... | 53 | ... | ... | 54 | ... | 55 |
| Breadth of tympanic bulla | ... | ... | ... | ... | 24 | ... | ... | 37? | ... | 25 |
| Length of mandible | ... | 769 | ... | ... | ... | ... | ... | 679 | ... | 842 |
| Length of symphysis | ... | 170 | ... | ... | ... | 184 | ... | 149 | ... | 176 |
| Depth of mandible at coronoid | ... | 153 | ... | ... | ... | ... | ... | 133 | ... | 153 |
a About 150 mm. lacking from end of beak. b A little abraded. c Taken on a level with the curve of the inner margin of the premaxillæ. Is only approximate.
SEX CHARACTERS.
It will be found from an examination of the foregoing descriptions that in those specimens in which the sex is known to be female, or is marked as such, the premaxillæ are comparatively narrow, the mesirostral ossification only slightly developed, the prenarial basin undeveloped, and the teeth quite slender, with a diameter of from 10 to 14 mm. As the teeth in some of them have closed roots there can be no doubt that they are adults. On the other hand, those skulls known or believed to be from adult males have the mesirostral ossification enormously developed, a deep prenarial basin, and fusiform teeth with closed roots and a diameter of from 25 to 30 mm. It appears to be a fact, therefore, that in the females the mesirostral ossification is never greatly developed at any age, that the teeth are never thick and fusiform, and that the prenarial region is never deeply concave. Immature individuals present, of course, the appearance of the females, except that the teeth are open at the root and that the mesirostral ossification is not developed at all. Conversely, the females, broadly speaking, always present characters of immaturity, but in adults the roots of the teeth are, of course, closed.
That these conclusions are correct is borne out by an examination of descriptions and figures of specimens from other parts of the world, for which purpose a few are available in the writings of New Zealand zoologists and others. Hector, for example, in 1873,[40] published a description and figures of a skull from the Chatham Islands which had a large mesirostral ossification, deep prenarial concavity, and large, thick teeth, having a diameter of 34 mm. This is the same combination of characters found in the Newport specimen, which is known to be a male, and the Bering Island skulls supposed to be those of males.[41]
In 1876,[42] Haast figured and described a female 26 feet long, and hence presumably adult, from Lyttleton Harbor, New Zealand, which had a small development only of the mesirostral ossification, a slight prenarial depression, and rather slender teeth with closed roots and a diameter of 19 mm. This combination of characters is found in the Barnegat skull, also known to be an adult female.
In the same paper Haast describes[43] and figures the skull of another female from Akaroa Harbor, New Zealand. This individual was larger than the last and was accompanied by a suckling calf. Hence, there can be no doubt that it was mature. The skull shows a moderate development of the mesirostral ossification, and slender cylindrical teeth with closed roots and a diameter of 16 mm.
It is demonstrated from the foregoing discussion, I think, that the sexes can be distinguished by the skulls, when adult, or by the teeth alone.
Reverting now to Ziphius gervaisii, which was mentioned on [p. 30] as perhaps constituting a separate species, it will be seen by examining the figures given by Gervais[44] of the skull on which it was based that the latter presents the combination of characters peculiar to the female of Z. cavirostris. This skull, which was from Aresquiers (Hérault), France, was 888 mm. long, and hence, presumably, adult. The mesirostral ossification is but slightly developed, the prenarial concavity moderate, the teeth small, slender, and cylindrical, with closed roots and a diameter of 14 mm. There seems to be no sufficient reason for regarding this skull as representing a species distinct from cavirostris.
The specimen from Buenos Ayres described and figured by Burmeister in 1868[45] was an immature male. In the skull the mesirostral ossification was lacking, the premaxillæ were flat, and the teeth conical and acuminate, with open roots, and a diameter of 12 mm. This individual was 12 feet 11½ inches (3.95 m.) long, and hence about as long as the Charleston specimen, but the skull was apparently 680 mm. long, while that of the Charleston specimen is 797 mm. long. In the latter the teeth are 45 mm. long and 10 mm. in diameter, while the tooth figured by Burmeister is 31 mm. long and 12 mm. in diameter. From these data it appears improbable that the sex of immature individuals can be determined from the skull or teeth.
TEETH.
The teeth of the various North Atlantic and North Pacific specimens merit a somewhat more detailed description than is given on pages [50] to [53]. Six pairs of teeth from six different individuals are available for comparison. Their dimensions are as follows:
Dimensions of the teeth of Ziphius cavirostris.
| Cat. No. | Locality. | Age. | Sex. | Teeth. | |
|---|---|---|---|---|---|
| Length. | Greatest diameter. | ||||
| mm. | mm. | ||||
| 21975 | Charleston, South Carolinaa | Young | Female | 45 | 10 |
| 20971 | Barnegat City, New Jersey | Adult | Female | 56 | 13 |
| 22069 | Bering Island | Adult | (Female?) | 41 | 14 |
| 20993 | dob | Adult | (Male?) | 48 | 25 |
| 21248 | do | Adult | (Male?) | 58 | 30 |
| 49599 | Newport, Rhode Island | Adult | Male | 63 | 29 |
a Type of Z. semijunctus. b Type of Z. grebnitzkii.
21975. Charleston, South Carolina.—Young female. (Type of Z. semijunctus.) The teeth are slender, conical, and acuminate, largest at the base and tipped for about 2 mm. with white enamel. The remainder of the teeth is coated with a thin layer of cement. The teeth in what appears to be their natural position protrude horizontally from the mandible for about 17 mm. They are slightly curved upward near the tip and are oval, or elliptical, in section, the transverse diameter being a little less than the vertical diameter. They are a little flattened externally. The surface is smooth. They are open at the root, and hollow. ([Pl. 38], figs. 1, 2; [pl. 22], fig. 1.)
Doctor Manigault, curator of the Charleston Museum, wrote to Professor Cope regarding these teeth, as follows:
Another peculiarity of the head consists in the lower maxillary bones being provided each at its point with a single small and very sharp tooth. These were not noticed during the dissection, owing to their being too much embedded in the integuments.[46]
20971. Barnegat City, New Jersey.—Adult female. The teeth are slender, cylindrical, and irregularly pointed at both ends. The tips show what appears to be an inner core of dentine which has been worn down nearly to the cement coating and somewhat fractured. The cement coating is several millimeters thick, but does not increase the diameter of the teeth near the middle, so that they remain irregularly cylindrical throughout. The surface of the cement is rough and irregular. The root is short, conical, and closed at the end. These teeth are nearly straight. As they have been extracted from the jaw and the latter is broken it is not possible to distinguish which is the upper and which the lower surface, but they are irregularly oval in section, and a little compressed. ([Pl. 38], figs. 3-5.)
In my original notes on this specimen, I recorded that there was a small pair of teeth behind the larger ones described above. Mention of these will be made again later. (See [p. 57].)
22069. Bering Island.—Adult female (?). The teeth are in position in this specimen and are nearly horizontal in position, but a little inclined upward and toward each other. They do not extend beyond the tip of the jaw nor up to the level of the upper surface of the symphysis, but protrude about 13 mm. beyond the alveoli on the side. They are rather slender, somewhat fusiform, blunt at both ends and slightly curved upward. The surface is irregular. They are nearly round in section. The root is closed, and the apex shows what appears to be a core of dentine surrounded by cement. There is a depression on the inner side near the root. These teeth are remarkable as intermediate in form between those of the preceding specimen and those of the specimens next to be mentioned. ([Pl. 38], figs. 6, 7; [pl. 22], fig. 3.)
20993. Bering Island.—Adult male (?). (Type of Z. grebnitzkii.) These teeth are almond-shaped and very symmetrical. They are thickest near the base and taper gradually to the tip, which is quite acute. They are somewhat compressed and hence elliptical in section, the vertical diameter being greater than the transverse diameter. One side (probably the inner) is flattened. They are slightly curved upward toward the apex, which is a little worn and fractured. The root is very short and conical. It is nearly closed, but a very small canal extends upward for about 10 mm. The surface of the tooth is quite smooth, but dull in the lower half. The line of demarcation between cement and dentine is not evident. ([Pl. 38], figs. 8, 9; [pl. 23], fig. 1.)
21248. Bering Island.—Adult male (?). In this specimen the teeth are still in the natural position in the jaw. They are held in place by ligaments and protrude far beyond the alveoli, only about one-ninth of their length being below the superior border. They incline forward at an angle of about 45° with the longitudinal axis of the jaw and diverge slightly at the tips.
The teeth themselves have the same general form as those of the preceding specimen, but are larger. The inner surface is flattened and the outer strongly convex. The tips are quite pointed, but show some indications of wear. The roots can not be seen distinctly, but appear to be closed. ([Pl. 22], fig. 4.)
49599. Newport, Rhode Island.—Adult male. These teeth are longer than those of the preceding specimen, and while they resemble the latter in general form, taper much more gradually to the tip. The root, or portion below the point of maximum girth, is much shorter than that above, and rugose, with several deep furrows. A very small circular opening at the base of the root marks the orifice of the nerve. The upper half of the teeth is smooth, and the tips slightly worn and fractured. The small elliptical worn area is situated on the convex side of the tooth, which appears to be the outer side. As the alveoli of the jaw are, however, filled with a network of bone, the teeth can not be inserted in them. They were detached when received. ([Pl. 38], figs. 10, 11; [pl. 22], fig. 2; [pl. 23], figs. 2, 3.)
Besides the difference in the size and form of the teeth in the two sexes, it is probable, as will be seen by consulting the foregoing data, that in the female the apex of the teeth does not extend more than a very small distance above the alveoli even in mature individuals, and probably often not more than a few millimeters; while in adult males the teeth are almost entirely protruded from the alveoli, which are filled with a coarse bony network. These differences are carried out in all the American specimens, and also characterized the New Zealand specimens, as may be learned from the accounts of Haast and Hector.
A number of rudimentary teeth in addition to the large terminal pair have been noted in the Aresquiers, Buenos Ayres, and perhaps other specimens, and two such teeth were found in the mandible of the Barnegat specimen, behind the large pair. One of these rudimentary teeth has been preserved. It is cylindrical and moderately curved. The length is 16 mm. and the diameter 2 mm. The whole tooth, with the exception of the extreme tip, is thickly coated with cement. The root is closed and the crown acute and apparently abraded by use. ([Pl. 38], fig. 5.)
Returning now to the question of the validity of grebnitzkii as a species, I would say that after comparing the measurements of the Bering Island skulls with those of the Atlantic coast specimens, and comparing the skulls themselves, I have been unable to find any constant difference of importance, except the size and form of the periotic bone. As the earbones are lacking from many of the skulls, the series available for comparison is small.
As compared with the Atlantic coast specimens, the anterior portion of the periotic bone in grebnitzkii is larger, broader, and more rectangular in outline when viewed from below. I observe, however, that the absolute size and outline of the periotic vary considerably in the different specimens of grebnitzkii without relation to age. The same appears to be true of cavirostris, but comparing the two series of skulls as a whole it appears to be true that the anterior mass of the periotic is larger in grebnitzkii. I do not think, however, that the latter species should be kept distinct on this account alone, at least until the character has been confirmed, and perhaps strengthened by others, through the examination of a larger series of specimens.
SKELETON OF ZIPHIUS FROM BERING ISLAND.
The Museum collection contains an incomplete skeleton of a very young individual, Cat. No. 22875, which was received from Bering Island with the skulls of Z. grebnitzkii, but does not belong to any one of them. Whether it really represents that species is, therefore, uncertain, but such is probably the case. The length of the vertebral column, consisting of 45 vertebræ, without interspaces, is 9 feet 2 inches.
The vertebral formula is as follows: C. 7; Th. 10; L. 10; Ca. 18 (+1?) = 45 (+1?). This is the same as in the type of semijunctus so far as the cervicals, thoracics, and lumbars are concerned, and the probable total is the same. In their general characters these vertebræ agree with those of the skeletons already described, but they present a number of differences as well. On account of immaturity the processes are even less developed than in semijunctus. All the epiphyses are free, and in the third to the seventh thoracic vertebræ the neural arch and spine are separate from the centrum. The centra are very short in proportion to their width.
Although the specimen is so young, the anterior foramen of the atlas is, nevertheless, inclosed by bone, and though the line of separation between the atlas and axis is visible on the sides, the fourth cervical is anchylosed to the third at the top of the centrum. Although the neural spines, metapophyses, and transverse processes of the thoracics are much shorter than those of the young semijunctus, the epiphyses are as large or even larger than in that specimen. The neural arches are also noticeably thicker than in semijunctus, and the centra are rounded inferiorly rather than carinated. The neural spines are much more nearly erect than in the adult Barnegat and Newport skeletons, but, as mentioned on [page 41], this is probably a character of immaturity, and is shared by semijunctus.
The differences as regards the form of the centra and neural arches die away among the lumbars, and these vertebræ and the caudals are, with a due allowance for greater immaturity, very similar to those of semijunctus.
The seventh thoracic is like the sixth in form, and is without a transverse process. It thus resembles the same vertebra in semijunctus. The eighth, however, has an ill-defined facet on the side of the metapophysis and a second facet a little above the upper border of the centrum. The eighth pair of ribs has only a single terminal articular facet.
The ninth thoracic has a short, thick transverse process, about in line with the upper surface of the centrum.
The transverse process of the seventh caudal is perforated on the right side by a foramen. The transverse processes are last traceable on the ninth caudal, the neural spines on the tenth caudal, and the neural arch on the eleventh caudal. Eight chevron bones are preserved, but probably two more were present originally.
Ten pairs of ribs are present. The first is much broader in the proximal half than in the distal half, but the distal end is slightly expanded. The first seven pairs possess both head and tubercle, but the eighth, ninth, and tenth have only a single terminal articular facet.
The sternum, which consists of five segments, is similar in form to that of semijunctus. The two sides of each segment are united. The posterior emargination of the third segment, and those of both ends of the fourth and fifth segments are small. The scapula and humerus are like those of semijunctus in form. The remaining parts of both pectoral limbs are lacking.
Without more material, and especially some skeletons of adults, it is difficult to decide what importance should be assigned to the differences observable in the cervical and thoracic vertebræ of this young Bering Island specimen. The measurements of the skeleton are included in the table on pages [47] and [48].
EXTERNAL CHARACTERS.
The series of photographs (Cat. No. 142579) of an individual obtained in Kiska Harbor, Alaska, is very interesting as affording comparison of what is apparently a specimen of grebnitzkii with the Atlantic form represented in the photograph of the Newport, Rhode Island, specimen. As no part of the Kiska specimen was preserved, it is not possible, of course, to identify it positively with grebnitzkii or even with the genus Ziphius. No one who compares the photographs reproduced in [Pl. 41], figs. 3 and 4, can, I think, fail to be convinced that both represent animals of the same genus and that the Pacific species (whether grebnitzkii or not) bears the strongest possible resemblance to the Atlantic one.
Doctor Egbert published the following note on the Kiska specimen in 1905:
Early in September a monster dolphin grounded on the beach in Kiska Harbor and was killed. Specific identification has not yet been made. The general color was bluish-gray; length, 18½ feet; estimated weight, 3,600 pounds; sex, male. Body was quite regular in shape and rather rotund, the greatest circumference being about midway between dorsal fin and tip of the rather short snout. This dolphin was hauled alongside the ship, stripped of its blubber, and the oil extracted. Some of the flesh was eaten. The oil obtained was of excellent quality. It was particularly desired for use on the wire of the deep-sea sounding machine used aboard the [U. S. Coast Survey steamer] Patterson.[47]
The size was about the same as that of the Newport specimen. Although Doctor Egbert gives the color merely as “bluish gray,” the photographs indicate that the belly was white, or whitish, and that there were oval white spots on the sides. As a whole, therefore, the coloration was similar to that of the New Zealand specimens of cavirostris obtained at Port Cooper and Lyttleton Harbor.
When compared with the photograph of the Newport specimen ([Pl. 41], fig. 4) it will be seen that the Kiska photograph represents an animal practically identical in general form, as well as in the general shape of the head, the length and form of the snout, the size and general shape of the pectoral fins. In the photograph of the Newport specimen the flukes are not well seen, but in the Kiska photograph the posterior median convexity peculiar to the ziphioids is clearly represented. The dorsal fin of the Newport specimen appears to be turned somewhat to one side and the tip crumpled, which makes it appear lower and somewhat longer and less pointed than that of the Kiska specimen. This may, of course, be a real difference, though such is probably not the case.
Considering the foregoing data relative to grebnitzkii as a whole, there is not in my opinion sufficient warrant at present for considering this form as a species distinct from cavirostris, and it should be added that no distinguishing characters were given in the original description.