386 PROCEEDINGS OF THE ACADEMY OF [1896. 



ceeds it in size. The dental foramen enters at a point as far poste- 

 rior to the M. II as the long diameter of the latter, about as in M. 

 mephitica. 



Measurements. m. m. 



Length of ramus from M. II inclusive, 29 



I^eugth of molar series ; 25 



Length of true molars ; 13 



Length of sectorial ; 10 

 Width of sectorial at heel ; 5.5 



Length of heel of sectorial ; 4.5 



Length of crown of M. II ; -3 



Depth of ramus at Pm. IV ; 9 



Depth of ramus at posterior body of M. I ; 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 fossidens sp. nov. 



Two species of the genus Mephitis Linn, occur in the bone de- 

 posit 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 

 table by which they may be distinguished from the best known re- 

 cent species, M. mephitica and M. putorius. I add here that Dr. 

 Merriara has endeavored to substantiate the reference of the latter 

 species to a separate genus under the name of Spilogale.* He gives 

 a list of characters which he regards as generic, but which are to 

 me specific only, as they only consist of proportions of the skull and 

 teeth. 



I. M. 1 with para- and metaconule forming a straight longi- 

 tudinal crest ; no posterior ledge. 

 Metaconid small, low ; inferior premolars 2-3 overlapping ; ento- 

 conid low ; 31. fossidens Cope. 



II. M. X with distinct V-shaped para- and metaconules sepa- 

 rated by a fossa inwardly. 

 Metaconid small, low ; inferior premolars 2-3 not overlapping ; 

 ramus, lower border rising posteriorly ; entoconid low ; 



M. orthostichus Cope. 



^Proceeeds. Acad. Nat. Sci., Phila., 1895, p. 447. 

 * North American Fauna, No. 4. 1890, p. 5. 



