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 jaw is 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 of _M. bidens_.
Genus ZIPHIUS Cuvier.
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_.