Although all the specimens of _Berardius bairdii_ are more or less
incomplete, two or three of the mandibular teeth have been preserved in
nearly every instance; namely, in the adult female from St. George
Island, the left anterior and right and left posterior; in the immature
male from the same island, both anterior teeth; in the Centerville beach
specimen, the left anterior and right (?) posterior teeth; in the skull
from Bering Island formerly regarded as the type, all four teeth; in the
very young skull from Bering Island, the left anterior and posterior
teeth.
Taken as a whole, these teeth are not larger than those found in the
specimens of _B. arnuxii_ thus far recorded, but in both species they
vary so much on account of age, or for other reasons, that a comparison
of dimensions is unsatisfactory. The dimensions are as follows:
_Dimensions of teeth of Berardius arnuxii and B. bairdii._
Column headings:
A: Greatest height.
B: Greatest breadth.
Species and locality. Sex and Length. Large Small Remarks.
age. tooth. tooth.
A B A B
_B. arnuxii._ ft. in. mm. mm. mm. mm.
Akaroa (Van Beneden. Male. 32 0 [a]90 90 66 40 From
Type). figure.[b]
New Brighton (Haast Male(?). 30 6 [a]73 63 47 31 From
and Flower). figure.
Port Nicholson (Knox (?) 27 0 [a]65 50 (?) (?) From
and Hector). figure.
Locality unknown (Van (?) (?) 72 53 51 30 From
Beneden and Gervais, figure.
pl. 21 _bis_).
_B. bairdii._
49725—Centerville, Male(?), 41 ± [a]83 65 53 28
California. adult.
49726—St. George Female, 40 5 [c]79 72 62 45
Island. adult.
49727—St. George Male, im. 25 0 [a]86 61 ... ...
Island.
142118—Bering Island Young. ... ... [a]50 37 31 31
[a] Tip more or less acute.
[b] Van Beneden’s measurements are slightly different.
[c] Tip much worn.
A description of the teeth of the different specimens of _B. bairdii_ is
subjoined.
_No. 142118._—Bering Island; young (new born?). Anterior tooth conical,
hollow, with thin walls. The lower half of the tooth is filled with a
mass of bony pulp, which is separable. The tooth is widest at the base,
and is without any constriction indicating the formation of a root. Outer
and inner surfaces slightly convex, the latter with several distinct
longitudinal furrows, which extend to the apex. The whole tooth has a
thin coating of cement, except the tip, for a length of about 10 mm.,
which is more nearly white, and consists, presumably, of dentine. The
tooth is very symmetrical, but rather more convex externally. The apex is
pointed, erect, and a little more convex externally than internally. (Pl.
39, figs. 1, 2.)
The posterior tooth is similar to the anterior one, but much shorter and
more blunt, and the longitudinal furrows are about equally distinct
externally and internally. The cement extends nearly to the apex, which
latter is very short and is directed backward.
_No. 49727._—St. George Island, Alaska; male, immature. Anterior teeth
conical, acute, somewhat unsymmetrical, rather more convex externally
than internally. The internal surface with a deep median longitudinal
groove, and others less distinct on each side near the base. Apex
slightly inclined forward and inward, convex externally, with a single
longitudinal groove; nearly flat internally, with, or without, a groove.
Base of tooth for about 17 mm. covered with longitudinal rugosities,
indicating that the root was about to close. It is open, however, the
walls of the tooth at the narrowest point being 8 mm. apart and the
cavity filled with dense bony pulp. The anterior and posterior outlines
of the teeth are irregular, being convex near the base, then slightly
concave, and again convex near the apex. When in the natural position,
these teeth protrude about 33 mm., or a little more than one-third their
height, above the alveolus. (Pl. 39, figs. 3, 4.)
Posterior teeth lacking.
_No. 49725._—Centerville beach, California; male (?), adult. Anterior
tooth conical, with anterior and posterior margins as in the last. Apex
considerably abraded and rounded off; not inclined inward or forward.
Internal and external surfaces nearly equally convex, but the former with
a broad median longitudinal groove. Root closed, the base of the tooth
for a breadth of about 30 mm. covered with rounded rugosities. The
inferior border slightly convex and the angles rounded off. When in the
natural position, somewhat more than one-half of the tooth protrudes
beyond the alveolus, and the tooth itself is inclined forward and
outward. (Pl. 39, fig. 5.)
Posterior tooth quite irregular in form, but the portion above the rugose
base or root conical. Inner surface flat and uneven. Outer surface convex
and rather rugose. The cement covers the whole tooth thickly to within
about 5 mm. of the apex, which latter is short, quite acute, and slightly
directed inward. It is convex externally and nearly flat internally. The
basal rugosity or root is conical, thicker than the rest of the tooth,
and unsymmetrical, being somewhat directed backward. It shows no opening
below. When in the natural position this tooth is strongly inclined
forward and outward, and only the tip for a length of 22 mm. protrudes
beyond the alveolus. (Pl. 39, fig. 6.)
_No. 49726._—St. George Island, Alaska; female, adult. Anterior tooth
conical, with the tip blunt, having been so much abraded that the dentine
does not extend beyond the coating of cement. The tip measures 26 by 19
mm. The external and internal surfaces of the tooth are about equally
convex and somewhat rugose without distinct furrows. The root is thicker
than the remainder of the tooth and very rugose. It is entirely closed
below, and the inferior outline is convex. Posterior tooth much
compressed, conical above the root, nearly flat internally and slightly
convex externally. Cement coating very thick and extending to within
about 5 mm. of the dentine apex, which latter is acute and very slightly
curved inward and backward. The root is very unsymmetrical, the posterior
portion being much longer than the anterior. The surface is very rugose,
and there is no opening whatever below. The inferior border is convex,
with an emargination near the center. (Pl. 39, figs. 7, 8.)
In the adult skull from Bering Island, which has been mounted and placed
on exhibition, the teeth are fixed in the alveoli so that their entire
length and the peculiarities of the basal portion can not be determined.
In general form, however, they resemble those of the preceding specimen
very closely. The anterior teeth are placed obliquely—that is, so that
the anterior margins of the two teeth are nearer together than the
posterior margins. The teeth are also somewhat inclined forward. The
posterior teeth are strongly inclined forward and a little outward.
The anterior teeth are rather concave along the middle internally and
convex externally. The portion above the alveoli is quite smooth.
The posterior teeth are moderately rugose above the alveoli. The whitish
tips of denture are conical, compressed, and rather acute. They extend 6
mm. above the denture, and are 11 mm. long at their base, and 6 mm.
thick.
The anterior teeth protrude about 45 mm. above the alveolus (internally);
their base at the alveolus is from 73 to 76 mm. long, and from 33 to 35
mm. thick. The posterior teeth extend about 18 mm. above the alveoli
(measured vertically from the alveolus), and the base of the visible
portion (measured along the alveolus) is from 30 to 34 mm. long and from
18 to 20 mm. thick. These teeth have an antero-external angular
enlargement of the cement, so that they are somewhat triangular in
horizontal section. (Pl. 30, fig. 3; pl. 31, fig. 5.)
The data available are insufficient to enable one to determine
satisfactorily whether the teeth differ materially in size in the two
sexes, but it appears probable that they do not.