VERTEBRATE REMAINS, PORT KENNEDY BONE DEPOSIT. 231 



character, but simply as evidence that the character is not an individual variation, 

 as compared with the Mephitis mephitica. In M. fossidens, described below, the 

 pms. 2-3 overlap extensively. 



Osmotherium spel.^um Cope (PI. XVIII, fig. 6). Proc. Acad. Nat. Sci. Phil., 1896, p. 385. [Type No. 67, 

 Mus. Acad. Nat Sci. Phila.] 



Represented by a left mandibular ramus which contains alveoli or roots of the 

 c. and pms. 4-2, with pm. 1 and ms. 1-2 perfectly preserved. 



The ramus is robust, and its inferior border rises from below the heel of m. 1 

 upward and posteriorly. In Mephitis mephitica the ramus is less robust, and the 

 inferior border begins to ascend below the posterior part of m. 2. The anterior 

 border of the masseteric fossa is not sharply defined. There are three mental fora- 

 mina, the first and second below pm. 2, and the third below pm. 1, the anterior 

 being the largest. The molar teeth are much like those of M. mephitica, but are 

 more robust. The metaconid is considerably smaller than the protoconid, as in 

 Mephitis putorius, and smaller than in M. mephitica. The borders of the heel are 

 strongly and equally elevated, enclosing the basin completely. The pm. 1 differs 

 from that of M. mephitica in presenting a flat face inward and posteriori}', which is 

 bounded externally by an angular ridge, as in M. fossidens. The crown of the 

 pm. 2 is mostly lost, but a short, flat, transverse heel remains, which is similar to 

 but smaller than that of the pm. 1. The anterior root of the pm. 2 is opposite the 

 posterior root of the pm. 3, while the pm. 4 is entirely and directly in front of the 

 anterior root of pm. 2, and exceeds it in size. The dental foramen enters at a point 

 as far posterior to the m. 2 as the long diameter of the latter, about as in 

 M. mephitica. 



Measurements. 



mm. 



Length of ramus from m. 2, inclusive ; 29 



" of molar series ; 25 



" of true molars; 13 



" of sectorial; 10 



Width of " at heel; 5.5 



Length of heel of sectorial ; 4.5 



" of crown of m. 2 ; 3 



Depth of ramus at pm. 4 ; 9 



" " at posterior border of m. 1 ; 9 



The only question as to the validity of this form that can arise, is due to its 

 similarity to Mephitis fossidens. See the description of the latter below. 



MEPHITIS Linn. 

 Spilogale Gray. 



Two species of this genus occur in the bone deposit in considerable abundance. 

 After a cursory examination I referred both of them to M. mephitica \ but a 

 thorough study convinces me that this reference must be reconsidered. I give a 



1 Proc. Acad. Nat. Sci. Phil., 1895, p. 447. 



