426 



EXTINCT MAMMALIA OF NORTH AMERICA. 



A tootli, figure 12, plate XXX, from the miocene formation of Virginia, originally 

 ascribed by me to the same species as the remains of a Seal described by Prof. Wy- 

 man, is very like the one above indicated. The crown is proportionately somewhat 

 narrower, but otherwise the tooth might be viewed as having belonged to the same 

 animal. Its measurements are as follow : 



Length of the crown, 5 lines ; breadth, 3 J Hues; thickness, 2J lines. 



Length of the fang, lOJ lines; breadth, 3 lines ; length of the entire tooth, 14 lines. 



The remaining two teeth from Charles County, ascribed by Prof. Cope to Squalodon 

 Wymani, are different from the jireceding, and it is uncertain whether they belong to 

 the same animal. They have more the usual appearance of the teeth of the Dol- 

 phins. Their crown is robust conical, hardly compressed, abruptly curved backward, 

 and without ridges defining the inner and outer surfaces, except a feeble one postero- 

 internally. The enamel is comparatively smooth. In one specimen, figure 11, plate 

 XXX, the crown abruptly curves a short distance from the base ; in the other from 

 near its middle. The fang is long, simple, and rather abruptly curved postero-inter- 

 nally towards the end. The measurements of the specimens are as follow; 



Length of the crown, 

 Breadth of the crown. 

 Thickness of the crown. 

 Length of the fang, . 

 Breadth of the fang, . 

 Entire length of the tooth, 



PHOCAGENEUS. 



Phocageneus vennstus. 



Fhoeodon, Agassiz : in Wyman's Notice Rem. Verteb. An., Amer. Jour. Sc. 18.50, X, 230, Fig. 4. 

 Squalodon menio, in part of Cojae : Proc. Ac. Nat. Sc. 1867, 152. 



li Phocodon is the same as Squalodon, the tooth represented in figure 4 accompany- 

 ing Prof. Wyman's Notice of Remains of Vertebrated Animals found at Richmond, 

 Va., is surely very unlike any of those more certainly ascribed to the latter. Having 

 requested Prof, Wyman to allow me to inspect the tooth, he sent me a specimen 

 which he observed was either the original of the figure or pertained to the same 

 animal. If such is the case, the figure is an unfaithful representation of it. The 

 specimen is represented in figure 10, plate XXIX, of the present work. 



The crown is conical, compressed, oval in section at base, and moderately curved. 

 It forms an acute ridge before and behind, and has an acute point. The base is con- 

 spicuously swollen internally, and contracts all around towards the neck. The ante- 

 rior acute border of the crown expands in a triangular surface of the swollen base. 



