nalones in the upper jaw are intermediate in size between the canines
and the middle incisors.
In the Stenorhynchus leptonyx each molar tooth in both jaws is
trilobed, the anterior and posterior accessory lobes curving towards
the principal one which is bent slightly backwards ; all the divisions
are sharp-pointed, and the crown of each molar thus resembles the
trident or fishing-spear; the two fangs of the first molar in both
jaws are connate. In Sten. serridens (PI. 132, fig. 4) the three anterior
molars on each side of both jaws are four-lobed, there being one
anterior and two posterior accessory lobes; the remaining posterior
molars (true molars) are five-lobed, the principal cusp having one
small lobe in front and three developed from its posterior margin;
the summits of the lobes are obtuse, and the posterior
ones are recurved like the principal lobe. Sometimes the third
molar below has three instead of two. posterior accessory lobes.
Occasionally, also, the second as well as the first molar above
has its fangs connate; but the essentially duplex nature of the
seemingly single fang, which is unfailingly manifested within by
the double pulp-cavity, is always outwardly indicated by the
median longitudinal opposite indentations of the implanted base.
These slight and unessential varieties, presented by the specimens
of the Saw-toothed Sterrink (Stenorhynchus serridens) brought
home by the enterprising Naturalists of Sir J. Ross’s Antarctic
expedition, accord with the analogous varieties noticed by the best
observers of the Seals of our neighbouring seas, as, for example,
Nillson.(l)
The Grey Seal (Halicheerus gryphus) of our own Seas begins, by
the extension of the connate condition of the two roots through a
greater proportion of the molar series, to manifest a transition to the
(1) A diligent labourer, in what our plain-speaking German fellow-zoologists call the
1 Gattungsmacherei’ has seized upon the variable mode of implantation of the anterior
premolars as ground for the generic distinction of Seals; and so by the following phrase,
"the 1st, 2 d and 3d front upper, and the 1st front lower grinder single-rooted, the rest 2 rooted,”(g)
my Stenorhynchus serridens is tied as a synonym to the tail of ‘ Lobodon carcinophaga, Gray.’
Not a single additional fact does the writer find to add to those characters which I first pointed
(o) Zoology of Ross’s Antarctic Voyage, Mammalia, p. 2, 4to. 1844.
family of Seals with true single-rooted molars ; the formula of this
genus, is:
Incisors — ; canines — ; premolars — ; molars — : = 34.
The four middle upper incisors are close set, with pointed recurved
crowns; the lateral incisors are much larger and laniariform: the canines
have moderate crowns, with a sharp ridge before and behind. The
crowns of the molar teeth (PI. 132, fig. 5) are conical, subcompressed,
longitudinally and finely grooved, with an anterior and posterior edge ;
those below have generally a slight notch at the fore and back part of
the base. The first molars, both above and below, are the smallest,
with a simple crown and a single ventricose fang; the second and
third above, and the second, third, and fourth below, have two
connate roots; the two roots are commonly distinct in the remaining
posterior molars : all the roots are very thick.
In the genus Otaria (ib. fig. 6) the dental formula, is :
Incisors ^ ; canines ^ ; premolars ^ ; molars ~ = 36.
The two middle incisors are small, subcompressed, with the crown
transversely notched ; the simple crowns of the four incisors below fit
into these notches : the outer incisors above are much larger with a
long pointed conical crown, like a small canine. The true canine is
twice as large as the adjoining incisor, and is rather less recurved.
The molars have each a single fang; the crown is conical, subcompressed,
pointed ; in the two last recurved, with a basal ridge or
* cingulum,’ broadest within g in the Otaria jubata, with a pointed
cusp developed from its fore-part, and in the last two molars also
from its back part. In some species, as the Otaria lobata, (Phoca
out aa distinguishing the Sten. serridens from the Sten. leptonyx, except the above-cited variety
respecting the implantation of the premolars; and even this is misinterpreted, the supposed
single root being essentially two roots eonnate. A re-examination of the specimens of Sten.
serridens, in comparison with Sten. leptonyx, has only impressed more strongly the truth of the
observation with which I concluded my description of that new species, “ the modifications of
the compressed and deep-cleft molars are not of sufficient importance to justify the introduction
of a new generic name into the group of amphibious or pinnigrade Carnivora, which has already
been overburthened in this way .’’(a)
(a) Annals of Nat. History, 1843, p. 331.