EXTINCT MAMMALIA OF NORTH AMERICA. 425 



differently shaped crown, may belong to the same animal, though of this there is no 

 more certain evidence than association and general relation of size and form. The 

 crown is longer and narrower than in the preceding specimen, and forms a simple 

 cone, slightly compressed and curved. Ridges defining the inner and outer surfaces 

 are almost obsolete, but the enamel is wrinkled nearly in the same manner as in the 

 preceding tooth. The fang is strongly curved and gibbous. The measurements of 

 the specimen are as follow : 



Length of the wown, 7 lines ; breadth, 5 lines; thickness, 4 lines. 

 Length of the fang, 22 lines ; greatest breadth, 6 lines. 

 Length of the tooth along the anterior curvature, 33 lines. 



A third tooth, accompanying the former specimens, in its perfect condition, had 

 about the same length as the second tooth, but was of more robust proportions. If it 

 belonged to the same animal it held a more posterior position in the jaw than the 

 othei's. The summit of the crown is broken off and it is eroded at the conjunction of 

 the fang. The crown is conical, curved and oval in section at base. It presents no 

 trace of ridges defining the inner and outer surfaces. The enamel appears less cor- 

 rugated than in the former specimens, but is probably worn. Postero-internally it is 

 longitudinally grooved. The fang is less curved and less tapering than in the pre- 

 ceding specimens, and it presents a median longitudinal groove internally. The 

 measurements of the specimen are as follow : 



Length of crown restored, 7J lines; breadth, 6 J lines; thickness, 4} lines. 

 Length of fang, 16 lines; breadth, 6i lines. 



Delphinodon Wymani. 



Fhoea Wymani, Leidy : Proc. Ac. Nat. So. 1856, 265. 



Squalodon Wymani, Cope : Proc. Ac. Nat. Sc. 1867, 132, 151, 152. 



Three teeth, from the miocene formation of Charles County, Maryland, ascribed by 

 Prof. Cope to a species of Squalodon, appear to me, at least in part, to belong to a 

 smaller species of Del]iliinodon. 



One of the teeth, figure 10, plate XXX, bears a resemblance to that first described 

 of the larger species. Its crown is proportionately longer, and the posterior tubercle 

 and internal curved ridge of the crown are rudimental, but it has the same general 

 form, with the abrupt curvature and slight twist of the summit backward and 

 inward. The ridges defining the inner and outer surfaces of the crown are alike in 

 their course, and the enamel is likewise wrinkled. The fang has also the same form, 

 but is comparatively less curved. The measurements of the specimen are as follow : 



Length of the crown, 5 lines ; breadth, 34 lines ; thickness, 3 lines. 

 Length of the fang, restored, 10 Jlines ; breadth, 3 J lines. 

 Length of the entire tooth restored, 14 lines. 



54 



