438 EXTINCT MAMMALIA OF NORTH AMERICA. 



formation of North Carolina. The specimen belonged to Prof. Emmons, and is repre- 

 sented in figure 33 of his Report of the North Carolina Geological Survey. 



The tooth bears a miniature resemblance to a cow horn, being conical, strongly 

 curved, and proportionately much broader approaching the ba.se than in the pre- 

 ceding species; nor does it assume a quadrate appearance, but is nearly circular or 

 ovoidal in transverse section. The deep conical pulp cavity is defined by a sharp 

 edge at the periphery of the base. The length of the tooth is about the same as that 

 of the curved tooth of 0. quadratidens, but its diameter at base is an inch, by an inch 

 and two lines. 



Recently Prof Cope has described a tooth from the miocene of Charles Co., Md., 

 which he refers to a species distinct from the preceding. The specimen, however, 

 agrees so nearly in its form and proportions with an equal length of the summit of 

 the tooth of 0. cornutidens, that I suspect it belongs to a younger individual of the 

 same, or a different part of the jaw in the adult. The specimen is two inches five 

 lines in length, and about eight in breadth. 



We know nothing of other remains of Oryderocetus than those indicated. When 

 we observe the variety in the form and size of the teeth in the Sperm Whale, we are 

 led to suspect that probably all the specimens referred to the several species of 

 Orycterocetus belong to one. 



HOPLOCETUS. 

 Hoplocetus obesus. 



Leidy : Proc. Ac. Nat. Sc. 1868, 196. 



Founded on specimens consisting of a tooth and the fragment of another, obtained 

 by Prof. Holmes from the post-pliocene deposit of Ashley River, in the vicinity of 

 Charleston, South Carolina. 



The nearly entire tooth, represented in figure 13, plate XXX, two-thirds the 

 diameter of the specimen, has a portion of the crown and the end of the 

 fang broken away. The crown was much worn, leaving on the summit a broad, 

 flat, discoidal surface. The enamel, where it remains, forms a band encircling about 

 one-third of the crown, about three lines in depth, and one-fourth of a line thick. It 

 appears to have been rugose longitudinally. The fang, a striking character in the 

 teeth referred to Hoplocetus, is fusiform, remarkably I'obust, and large in proportion 

 to the crowii. It is straight at the bottom two-thirds, but curved towards the crown, 

 so that this appears to be obliquely implanted upon it. The interior of the fang is 

 pervaded by a narrow pulp cavity of irreguhir diameter, from the existence at its 

 sides of nodosities. The part constituting the technical neck of the tooth is feebly 

 constricted. The measurements of the specimen are as follow: 



