Vol. 4 J Sinclair. — Mammalia from Quaternary Caves. 161 



MEG ALONYX WHEATLEYI Cope (?). 

 PI. 23, Fig. 7. 

 Locality. — Potter Creek Gave. 



A single specimen (No. 8203) is referred to this species. It 

 has the characteristic triangular form of the superior molars of 

 Mcgalonyx, with the apex of the triangle rounded and the base 

 slightly grooved. The remaining faces are respectively plane 

 and convex. In dimensions, it agrees with Cope's Megalonyx 

 wheatleyi, and in the absence of negative characters has been re- 

 ferred to that species. Megalonyx wheatleyi was described from 

 material collected from the ossiferous deposit filling a fissure ex- 

 posed in a quarry at Port Kennedy, Pennsylvania. The poster- 

 ior molars can be distinguished from those of Megalonyx jef- 

 fersonii only by their inferior size. The tooth from the Potter 

 Creek Cave is intermediate in this respect between Nothrother- 

 ium sJiastense and M. sierrensis. It is slightly wider at the 

 base of the pulp canal than at the triturating surface, indicating 



that the animal was not fully mature. 



Measurements. 



Anteroposterior diameter of molar at triturating surface.... 12 



Antero-posterior diameter of molar at margin of pulp canal. . . 12.5 



Transverse diameter of molar at triturating surface 19.5 



Transverse diameter of molar at margin of pulp canal 20.5 



MEGALONYX JEFPERSONII Leidv ( ? ) . 

 Locality. — Potter Creek Cave. 



This identification is based on a fragmentary canine-molar 

 (No. 8620) which agrees in dimensions with Megalonyx jeffer- 

 sonii. Although not much curved, the obliquity of a small part 

 of the triturating surface preserved indicates that the tooth 

 probably belongs to the superior series. The convex rib is situ- 

 ated midway on the inner side of the tooth with a well marked 

 concavity on either side. It is possible that this tooth should be 

 referred to Megalonyx sierrensis, in which the upper molars 

 are not known, but the convex rib in the lower canine-molars of 

 that species is less centrally located than in the specimen in 

 question. If the tooth were entire, the measurements given below 

 would be slightly increased. In particular, the antero-posterior 

 diameter would be lengthened one or two millimeters. 



Measurements. 



Antero-posterior diameter of canine-molar 34mm 



Transverse diameter of canine-molar 16 



