Since the foregoing account ofeuropæuswas written, a description of the type-skull, with two excellent photographic figures, has been published by L. Brasil,[29]of the Caën Museum. A comparison of the figures with those of the Atlantic City and Long Branch skulls on Pls.2and8of the present article, confirms the identification of the latter specimens withM. europæus. Besides a brief description of the type-skull M. Brasil’s paper contains measurements and two text figures of the right mandibular tooth, natural size.
This species was originally described from a single cranium of a young individual, which was collected by Dr. L. Stejneger on Bering Island, Commander Group, Bering Sea, in 1883. With but a single skull, the characters of the species could not be very satisfactorily defined, and some European cetologists have been inclined to doubt its validity.[30]In 1904, however, another skull was obtained by the National Museum, which made it certain that the species was entirely distinct fromM. bidensor other known forms of the genus. Early in the year mentioned Dr. D. S. Jordan, president of Stanford University, called my attention to a small whale, which stranded on the coast of Oregon, 1½ miles south of the United States life-saving station on South Beach, Yaquina Bay, near Newport, in February, and proved later to represent the present species. Doctor Jordan’s information was obtained from Mr. J. G. Crawford, of Albany, Oregon, who wrote him in part as follows, under date of March 7, 1904:
Herewith I enclose a stereograph of a head of a member of the whale family, which I made at Yaquina Bay, Oregon. The animal was 17 feet long, with fluked tail, soft, smooth skin, blowhole on top of head, and two tusks in the mandible, but no [other] teeth in the mouth. The tusks are thin and apparently hollow. Length of head, 32 inches; width, 14 inches; height, 11 inches; blowhole, 5 inches. Eyes low on head. Width of mandible [jaw] at end: Upper, 1½ inches; lower, 1¾ inches. Width between tusks, 3 inches. The blubber was about 2 inches thick on the head. It went ashore about the 15th of February, 1½ miles south of the life-saving station on South Beach, 2½ miles south of Newport, Oregon. The head had been severed before I arrived.
Herewith I enclose a stereograph of a head of a member of the whale family, which I made at Yaquina Bay, Oregon. The animal was 17 feet long, with fluked tail, soft, smooth skin, blowhole on top of head, and two tusks in the mandible, but no [other] teeth in the mouth. The tusks are thin and apparently hollow. Length of head, 32 inches; width, 14 inches; height, 11 inches; blowhole, 5 inches. Eyes low on head. Width of mandible [jaw] at end: Upper, 1½ inches; lower, 1¾ inches. Width between tusks, 3 inches. The blubber was about 2 inches thick on the head. It went ashore about the 15th of February, 1½ miles south of the life-saving station on South Beach, 2½ miles south of Newport, Oregon. The head had been severed before I arrived.
A clipping from theOregoniannewspaper contains the following:
Albany, Oregon, March 2 [1904]. A peculiar specimen of the whale variety has been reported on the Oregon coast, near Newport. J. G. Crawford, of Albany, has just returned from a trip to Newport, where he made a picture of the head of the strange animal. The body was washed upon the beach during the recent storm which swept the coast. It is about 15 feet long. * * * Residents of the vicinity say they have never seen anything like it on the Oregon coast. * * * On either side of the mouth are two villainous-looking tusks several inches in length. They are at the back of the mouth, and extend up to a level with the top of the upper jaw. They are very wide and flat, squared on top. The mouth has no other teeth. * * *The head is equipped with a blowhole, like that of a whale. The eyes are very low, almost underneath the lower jaws.The body is in a good state of preservation, the flesh having been torn but little by the birds.
Albany, Oregon, March 2 [1904]. A peculiar specimen of the whale variety has been reported on the Oregon coast, near Newport. J. G. Crawford, of Albany, has just returned from a trip to Newport, where he made a picture of the head of the strange animal. The body was washed upon the beach during the recent storm which swept the coast. It is about 15 feet long. * * * Residents of the vicinity say they have never seen anything like it on the Oregon coast. * * * On either side of the mouth are two villainous-looking tusks several inches in length. They are at the back of the mouth, and extend up to a level with the top of the upper jaw. They are very wide and flat, squared on top. The mouth has no other teeth. * * *
The head is equipped with a blowhole, like that of a whale. The eyes are very low, almost underneath the lower jaws.
The body is in a good state of preservation, the flesh having been torn but little by the birds.
On receipt of the foregoing information, letters were immediately addressed to Mr. Crawford and also to the keeper of the life-saving station at South Beach, Capt. Otto Wellander, asking that, if possible, the entire skeleton be preserved. Captain Wellander replied that the whale had not been dead long when washed ashore; that he had tried to find the body, but that the high tides had either carried it away or buried it under driftwood.
The skull when cleaned passed into the possession of Mr. J. G. Crawford, who sent to the Museum some excellent photographs of it, and also of the head before the flesh had been removed. Later he sent the skull itself to the Museum for my examination, and finally very generously presented it to the Museum in exchange.
The skull is that of an adult individual, in nearly perfect condition, with the mandible and teeth. The parts missing are the left malar, the left tympanic bone, the distal ends of the pterygoids and the proximal ends of the premaxillæ. (Pl. 3, fig. 2.)
The Oregon skull exhibits all the characters included in the original diagnosis of the species,[31]but two of these, namely, the lack of a groove in front of the premaxillary foramen, and the vertical position of the premaxillæ distally, I do not at present consider of any importance, as they are shared byM. bidens. The species, as represented by the Oregon skull, however, presents other characters which clearly differentiate it from any other species of the genius. As it is without a basirostral groove, it allies itself in that respect toM. bidens,europæus, andhectori. Unlike those species, it has the premaxillary foramen behind the maxillary foramen, and in this respect resemblesdensirostrisandgrayi. Perhaps the most salient characters in whichstejnegeridiffers frombidensand all other known species are the erect position and flat surface of the supraoccipital and the very prominent backward extension of the frontal plate of the maxilla. This backward extension is so great that when the beak is horizontal a vertical line through the posterior margin of the maxilla passes considerably behind the temporal fossa. The only species which approachesstejnegeriin this respect ishectori, but in the latter the supraoccipital instead of being flat above the condyles is very strongly convex.
Another very marked character ofstejnegeriis that the extension of the lateral free margin of the orbital plate of the frontal, anterior to the orbit, is equal to the length of the orbit itself. Inbidensand all other known species this extension is only from one-third to one-half the length of the orbit. Numerous other distinguishing characters will be mentioned in the course of the following description ofstejnegeri, which is drawn from the adult Oregon skull, but modified when necessary by reference to the type skull from Bering Island. Comparisons are made chiefly withM. bidens, which is on the whole the best known species.
In the Oregon skull ofstejnegeri, the breadth between the post-orbital processes does not exceed the length from the occipital condyles to the maxillary notches. The skull is, therefore, narrower in proportion to its length than in any other species of the genus excepthectori, as represented by the skull figured by Flower. This skull was, however, that of a young individual. It is probable that in adults of this species the skull is broader than instejnegeri.
In the latter species, again, the length of the brain-case, between the occipital condyles and the maxillary notches, is just equal to the distance from the latter point to the distal end of the maxillæ, and the rostrum, including the premaxillæ, is much shorter than in other species ofMesoplodon, excepthectori, as represented by the young skull above mentioned.
The foramen magnum is very small, being less in width than the condyle on either side of it. In this respect it differs widely frombidensand other species (as far as can be ascertained from the figures available), excepteuropæus, in which the relative size is about the same.
The supraoccipital rises vertically above each condyle to the very top of the skull, being neither convex nor strongly bent forward as in other species, and especiallybidens. In the median line, however, while the occipital bone is flat immediately above the foramen magnum, it is deeply concave higher up and without a median ridge. The outline of the occipital crest, viewed from behind, is semicircular. In all the foregoing characters the occipital region differs widely from that ofbidensand other species. The only close resemblance is found in the old skull ofeuropæusfrom Long Branch, New Jersey, and even here the sides of the occipital above are far less prominent, their outline is much more convex, the occipital crest is angular, and the median depression is less pronounced.
Dorsal aspect(Pl. 3, figs. 1, 2).—The most noticeable feature of the upper surface of the skull is the large backward extension of the frontal plates of the maxillæ, the free margins of which converge strongly. The outline of the anteorbital region is rounded. The anteorbital notch is a shallow emargination. Anterior to this is a second still shallower emargination, the “pseudo-notch.” The margin between the two is much thickened, but does not form a distinct projection or tubercle, as inbidensand other species. The superior orifices of the nares are unsymmetrical as regards position, the left being somewhat in advance of the right. The maxillæ are concave around the maxillary foramen, and external to this foramen is an elongated ridge about as ineuropæus. The rostral portion of the maxillæ is broad at the base but tapers more rapidly than inbidens. The margin is thick. At the middle of the beak the outline of the maxillæ at a lower level is visible from above, which is not the case inbidensoreuropæus. The rostral portion of the premaxillæ is oblique proximally and vertical distally. Unlikebidens, these edges are sharp throughout. The mesethmoid ends opposite the maxillary foramina. Anterior to it is seen the concave upper surface of the vomer, which, however, becomes flat distally. At about the middle of the beak the anterior end is clasped by the posterior forked end of a “mesirostral” ossification, which has a convex surface. This ossification begins proximally below the edges of the premaxillæ, but its surface rises gradually anteriorly, and at the end of the beak it is much abovethe premaxillæ. The end of the beak consists of the consolidated mass of the premaxillæ and mesirostral ossification, the whole being convex above and below, but flat on the sides. The ossification has a deep median groove, which reaches to within 95 mm. of the tip of the beak.
It will be seen that the conformation of the upper surface of the beak is quite different from that ofbidensor any other species.
The maxillary foramina are large and directed forward, and have a distinct broad channel in front of them. In the Oregon skull the right foramen is single, but the left divided into two. The premaxillary foramina are a little behind the maxillary foramina. The distance between the maxillary foramina is less than that from the median line to the anteorbital notch. Inbidensit is much greater.
Lateral aspect(Pl. 9, figs. 1, 2).—A most noteworthy feature of the skull when viewed from the side is the great length between the orbit and the maxillary notch, which far exceeds that found inbidensand other species, being equal to the length of the orbit itself. The latter is about as long as the temporal fossa, which is somewhat flattened above, as ineuropæus. The outline of the supraoccipital is straight and nearly vertical. The zygomatic is more massive even thaneuropæusand is especially thick below. The inferior outline of the beak is convex proximally as ineuropæusandlayardi. There is no basirostral groove, the edges of the maxillæ being very thick in front of the maxillary notch. Over the orbit the maxillæ are thick and beveled, but not raised as inbowdoini.
Ventral aspect(Pl. 6, figs. 1, 2).—The beak is convex in the proximal half, much as ineuropæus, but farther forward is concave, except in the median line, where there is a narrow ridge formed proximally by the vomer, which in the type skull appears as a narrow lozenge 60 mm. long. In the adult Oregon skull it is anchylosed with the premaxillæ. The maxillæ extend to within 107 mm. of the end of the beak. The under surface of the beak is much more like that ofeuropæusthan ofbidens.
A narrow strip of the palatines extends around the base of the pterygoids in front, but the two strips do not meet in the median line. In the type-skull they do not extend inside the pterygoids. The expanded anterior end of the malar is very long and also forms the bottom of the maxillary notch, which is the case ineuropæusbut not inbidens. The inferior borders of the pterygoids are convex anteriorly, as ineuropæus, and are continued laterally, so that the sinus is deep as in that species. The lachrymal is very long, the free margin having a length of 55 mm. The posterior margin of the zygomatic process is concave, rather than convex as inbidens.
The tympanic bulla does not differ materially from that ofbidensin size or shape, as far as can be judged from the figures given in Van Beneden and Gervais’ Osteography (plate 26, figs. 4, 4a). The periotic is similar in size to the same bone inbidens, but the posterior end is more narrowly pointed and the anterior end is much lower, relatively. Ineuropæus, as far as can be determined from the material at hand, the form and size of the earbone is similar to that ofstejnegeri, but in the latter the anterior margin of the tympanic bulla is more nearly transverse and the posterior inferior groove is curved. (Pl. 35, fig. 2.)
In the Annisquam skull, supposed to representdensirostris, although from a young individual, the earbone is very much larger, especially the periotic, which is also quite differently shaped.
The mandible ofstejnegeriis much broken in the region of the angle on both sides, but otherwise complete. As compared with a mandible of an adultbidens, the most conspicuous differences are the shortness of the symphysis, the sharp upward bend of the inferior margin anteriorly, and the large size of the alveolus. The symphysis in the adult Oregon specimen ofstejnegeriis 140 mm. long, or scarcely more than in the young specimen ofeuropæusfrom New Jersey, and exactly the same as in the adult type-specimen of the latter species, as figured by Van Beneden and Gervais. The alveolus lies entirely behind the symphysis, its anterior end being 160 mm. from the anterior end of the jaw. It is 113 mm. long and 18 mm. wide. The mandible is 62 mm. high at its middle point. The coronoid process is more anteriorly situated than inbidensand the portion of the posterior margin of the ramus which remains indicates that the angle was strongly directed backward. (Pl. 11, fig. 4;pl. 12, fig. 1.)
The teeth are remarkable for their size and form. They are somewhat more than twice as broad as teeth of adult males ofbidens, as shown by the figures of Lankester[32]and Grieg,[33]and also a little longer. They are, in fact, probably broader than, or at least as broad as, the teeth of any other species ofMesoplodon, not exceptinglayardi. Sir William Turner remarks regarding a specimen oflayardiexamined by him that “the breadth of the tooth, where it emerged from the alveolus, was 3½ inches.”[34]He does not state, however, whether the measurement was taken along the top of the alveolus, at an angle with the transverse axis of the tooth, or along the transverse axis itself. At all events, the teeth figured by Owen and others are much less than 3½ inches broad. The teeth of adulteuropæusare only 2 inches broad, and ofbidens, as already stated, 1½ inches broad.
Instejnegeri(Pl. 12, figs. 1-3) the portion of the tooth above the alveolus is inclined slightly inward and backward, but the pointed tip curves outward so as to be vertical. When extracted from the alveolus, the whole tooth is found to be concave internally and convex externally. The posterior margin is convex and the anterior sinuous, a slight convexity occurring on the portion which projects above the alveolus. In this place the outer coating of cement is broken through, showing the underlying dentine or osteo-dentine, which is somewhat corroded or absorbed. This is particularly noticeable on the left tooth.
The upper margin of the tooth is transverse, or nearly at right angles with the anterior and posterior margins. The posterior angle is rounded and the anterior raised into an acute point by the projection of the dentine as a distinct, sharp cusp.The inferior end of the tooth is cut off obliquely and the margin is broken by numerous prominent rugosities. The surface of all that part of the tooth which is contained in the alveolus and covered by the gum above it is rugose, while the part above the gum is quite smooth and highly polished.
The right tooth has the following dimensions (in straight lines): Length of anterior border, 150 mm.; length of posterior border, 107; length of superior border, 54; length of inferior border, 86; average length of exposed dentine tip, 10; greatest breadth of tooth, antero-posteriorly, 81; greatest breadth of tooth, transversely, 15; distance from center of base of exposed portion, when in position in the alveolus, to tip of dentine projection, 82; distance from center of base of portion above the gum to tip of dentine projection, 70; distance from center of base of portion above the gum to center of inferior margin, 76.
The dimensions of the skulls are as follows, those of the type-specimen having been revised and corrected:
Dimensions of two skulls of M. stejnegeri.
The photograph of the head (Pl. 40, fig. 4) shows that the end of the beak was quite blunt, and the lower jaw quite a little longer than the upper. The superior margin of the lower jaw, which is concave in front of the tooth, is strongly convex and elevated at the side of it and behind it. The inferior margin of the upper jawis straight anteriorly, but farther back appears to be pressed upward by the tooth. An examination of the skull shows that the mandible can be lowered so that the teeth are below the upper jaw, but when so lowered the space between the teeth and the upper jaw on each side is barely a quarter of an inch (6 mm.). With the integuments in place, it is doubtful whether the mouth could be opened any wider than is shown in the photograph. The convexity of the head, shape of the blowhole, position of the eye, etc., do not appear to differ materially from the same characters in adults ofM. bidens.
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 ofZiphius, or at most two species, exist at present.[35]
Nearly all the skulls in European museums are assigned by the zoologists mentioned toZ. cavirostrisproper, 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 concerningZ. gervaisii. I find that wherever the characters above mentioned occur the sex (when known) is female. There is every reason, therefore, to believe thatZ. gervaisiiis the female ofZ. cavirostris.[36]I will return to this point again later.
In 1865 Cope described a species from Charleston, South Carolina, under the name ofHyperoödon semijunctus. In 1886 I referred it to the genusZiphius, butwas in doubt as to its specific identity. I thought that it might representZ. 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 ofZ. 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 withZ. 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 representingZ. 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 ofHyperoödon semijunctusCope. 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 speciesZ. grebnitzkii:
4. Cat. No. 20993. Skull of a male (?).[37]Collected by Dr. L. Stejneger in Bering Island, 1882. Orig. No. 1521. Type ofZiphius 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 genusZiphius, 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 NewZealand 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 speciesZ. 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, seepage 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 ofZ. cavirostris.
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 tugMonroe, 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.
The breadth of the pectoral fin, as shown by the skeleton, was 5¾ inches.
The photograph, which is reproduced inPl. 41, fig. 4, gives a good idea of the general form of the animal.
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.)
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 indiameter. 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.)
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 toZ. cavirostris.
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, whitebelow, 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.
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 trustworthyZ. cavirostrismust 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.
The type-specimen ofZiphius 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, butas the shape of the premaxillæ is similar to that found in the nominal speciesgervaisii, it might be thought necessary to refersemijunctusto the latter species. As will be shown later, however, this form of the premaxillæ appears to be characteristic of the adult female ofcavirostris, 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 ofsemijunctuswhich might be regarded as specific. This is that the lachrymal bone is thick distally, and cut off square at the end. In other specimens ofZiphiusexamined 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.
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 aZiphiusskeleton 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.
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.