418 EXTINCT MAMMALIA OF NORTH AMERICA. 



Squalodon atlanticus, from the miocene formation of Charles Co., Maryland. Two of 

 the specimens consist of portions of both maxillary bones, eacli containing three teeth 

 nearly like those above described. They belonged to a younger animal, as they ap- 

 pear unworn. The crowns are rather longer in relation with their breadth than in 

 two of the teeth from New Jersey, but approach in this respect the third of the latter. 

 The enamel is less sti'ongly wrinkled than in the New Jersey teeth; but the differ- 

 ences mentioned are probably not of specific value. 



The jaw fragments are about seven inches in length, and in the space of six inches 

 were provided with five double-fanged molar teeth. The back ones are obliquely in- 

 serted, so that the fore part of those behind is overlapped by the base of those in 

 front, and only the anterior teeth were more widely separated with appreciable in- 

 tervals. 



A caniniform tooth, from the same locality as the preceding, probably pertains to 

 the same species. When perfect, following its curve it has measured four inches in 

 length. The crown has measured an inch and a half, with the diameter at base nine 

 lines fore and aft and six lines transversely. The inner and outer surfaces, defined 

 by sub-acute ridges, are subdivided into narrow j^lanes or shallow grooves, and are 

 feebly roughened except near the base, where they are strongly wrinkled. 



Figure 18, plate XXX, represents one of the jaw fragments above mentioned, with 

 the first tooth of the series introduced from the opposite side. 



Squalodon Holmesii. 



Colophonodon, IJolmesii, Leidy : Proc. Ac. Nat. Sc. 1853, 377. 

 Squalodon IJohnesii, Leidy: Cope in Proc. Ac. Nat. Sc. 1867, 151, 153. 



Specimens of long, narrow, fusiform teeth, slightly curved and nearly straight, from 

 the eocene formation of the Ashley River, South Carolina, which have been referred 

 to a peculiar genus under tlie name of CoJoplionodon, by comparison with Beneden's 

 plates of Squalodonts* are seen to be incisors of a similar animal. 



A nearly perfect specimen is represented in figure 15, plate XXVIII. The crown 

 is a narrow cone, subdivided by a pair of acute linear ridges, in the position of which 

 it is of slightly greater diameter. The point of the crown is broken off. The enamel 

 is generally smooth and shining, and presents a few slight linear wrinkles near the 

 middle of the two surfaces of the crown. It extends farther down on the inner side 

 of the tooth, and at the base of the crown appears worn oif irregularly. The fang is 

 more than double the length of the crown, moderately curved, fusiform, and gibbous. 

 The gibbosity on the convex part of the fang is grooved. The tooth appears solid 

 throughout, and when perfect has measured over three inches long. Its crown has 

 been about an inch long, by three and a quarter and three and a half lines in diame- 



* Uecherclies sur les Sqiuiloauns. Mem. de I'Aead. Roy. de Belg. 1865, XXXIV, Pis. I, III, aud 1867, 

 XXXVII, Plate. 



