Teeth 2, on sides of lower jaw, strap-shaped, produced, arched, obliquely truncate at the end, with a conical process on the front of the terminal edge.
Lower jaw, Chatham Islands, obtained by Mr. H. Travers.
The total length of this jaw is 2 feet 9 inches; the posterior third is thin, convex externally, expanded, having a height of 6 inches. It is then straight, and compressed in its middle third as far as the commencement of the symphysis, which unites the rami for their anterior third into a straight
|I. Genus Hyperoodon, Lacépède.|
|H. rostratus, Wesmael.|
|H. latifrons, Gray.|
|II. Genus Ziphius, Cuvier.|
|Z. cavirostris, Cuvier.|
|Z. indicus, Van Beneden.|
|Z. (Petrorhynchus) capensis, Gray.|
|Z. (Epiodon) australis, Bur.|
|Z. (Epiodon) chathamiensis.|
|III. Genus Mesoplodon, Gervais.|
|M. (Ziphius) sowerbiensis, Gervais.|
|M. (Z.) layardii, Gray.|
|M. densirostris, De Blainville.|
|IV. Genus Berardius, Duvernoy.|
|B. arnuxii, Duv.|
conical beak, channelled above and rounded below. The binder edge of the tooth is 18 inches from the condyle, the width of the base of the tooth is 5 inches, and its anterior margin is 1½ inches in advance of the commencement of the symphysis. The lower margin of the jaw is swollen opposite the insertion of the teeth, which are deeply inserted, and slope obliquely backwards, with a decided incurvature towards the mesial line. The teeth are 6 inches long, 3 inches wide, and ¾ inch thick. The acute point on the upper angle is very marked, and the anterior edge is worn into a deep notch, with a rough surface showing the laminated structure of the tooth. It is implanted in the jaw by seven or eight fang-like processes, as if formed by the fusion together of a number of teeth.
There is no socket or notch in the jaw posterior to the tooth, the upper edge of the jaw being sharply defined, but from the tooth forwards there is a distinct dental groove showing the remains of alveolar processes.
The species to which I refer the jaw is only known from a single specimen obtained at the Cape of Good Hope, which differs in the greater height and more marked incurvature of the teeth. As it is a larger individual, the lower jaw measuring 3 feet, this difference may be due to age or sex.