1896.] NATURAL SCIENCES OF PHILADELPHIA. 387 



III. M. i without metaconule, but with a broad posterior 

 ledge ; paraconule V-shaped. 

 Metaconid small ; premolars not overlapping ; ramus not rising 

 posteriorly ; smaller ; 31. pxdorius L. 



Metaconid large ; premolars not overlapping ; ramus rising poste- 

 riorly ; smaller ; entoconid elevated : larger ; M. mephitica L. 



The characters above assigned to the species of Mephitis are es- 

 tablished by numerous specimens. There are twenty-eight individ- 

 uals represented by jaws and teeth in the Port Kennedy collection. 

 Of them I can only determine fifteen. My own collection and that 

 of the Academy of Natural Sciences include a number of skulls 

 of M. mephitica, while the collection of Mr. S. N. Rhoads includes 

 as many more, which he has kindly placed at my disposal. For 

 my knowledge of the cranial dentition of M. putorius series I am 

 also indebted to Mr. Rhoads, and to the monograph by Dr. Mer- 

 riam above cited. 



A species of this genus was found by me in a cave breccia in 

 Wythe County, Virginia, and a left mandible ramus with complete 

 dentition was obtained. I described it under the name Galera per- 

 dicicla.^ Dr. Coues has suggested that this species was founded on 

 a specimen of Mephitis putorius, and on a reexamination of the 

 specimen I am inclined to believe that he is correct. 



Mephitis fossidens^ is represented by parts of the jaws with teeth 

 of eight individuals. In only one of these do superior and inferior 

 molars occur together, and this one is, therefore, regarded as the 

 type. The species is of the same size as 31. mephitica, and was 

 supposed at first to be identical with that animal, until further study 

 revealed several important differences. 



The peculiarities of the dentition have been already pointed out 

 in the synopsis of species. These are found in the relations of the 

 paraconule and metaconule of the M. -, in the small metaconid of 

 the inferior sectorial, and iu the overlapping of the premolars. 

 The character of the M. 4- is seen in three specimens ; of the ante- 

 rior premolars in one, and of the inferior sectorial in six. The an- 

 terior portions of the mandibular rami are often injured, and the 

 canine teeth are preserved in only two specimens, and the incisors 

 in none. 



* Proceeds. Amer. Philos. Soc, 1869, p. 177, PI. Ill, fig. 1. 



* Fur Bearing Animals, 1877, p. 2 i. 



