CRANIAL CHARACTERS OF MEPHITIX.E, 189 



in Mephites and Spilogale is ml, or almost so ; that is, the palate 

 ends nearly or exactly opposite the posterior border of the last 

 molar. In Conepatus, the palate reaches a little farther back, 

 but still not nearly half-way to the ends of the pterygoids. In 

 other Ii^orth American Miistelldce, the palate usually extends 

 half-way or more to the extremities of the pterygoids. The 

 cranium of the Mephitinw is further peculiar in the periotic 

 region. The auditory bullae themselves are small, and but 

 moderately inflated at the base, with well-marked constriction 

 of a tubular meatus;* while the parts lying behind the bulliie 

 are unusually expanded, presenting a flattish and more or less 

 horizontal large surface, which widely separates the paroccip- 

 ital processes from the bulhT.t In Lutrincv and Enliydrince, the 

 paroccipitals are remote from the bullae, but there is no such 

 inflation of the mastoid region as is witnessed in some of the 

 Mephitincv, as in Spilogale, where the swelling of the mastoid 

 cells results in a convexity of the parts only less than that of 

 the bullpe themselves. The anteorbital foramen is remarkably 

 small, circular, canal-like, and occasionally divided into several 

 smaller openings. The postorbital processes are small or 

 obsolete; the postorbital constriction of the skull is compar- 

 atively slight. The glenoid fossa is shallow, presenting much 

 forward as well as downward, and never locks the condyle of 

 the jaw, as so often happens in Melimv. The coronoid process 

 of the mandible is variable in Mephitincv, for while in Mephitis 

 and SpilogaJe it is erect and conical, as usual in Mustelidcv, in 

 Conepatus it takes a backward slope, and is obtusely falcate, as 

 in Enhydrime. 



The teeth of Mephitincv are also diagnostic in the combina- 

 tion of a large quadrate back upper molar with pm. || or 3^ (the 

 latter formula peculiar to Conepatus, but not always obtaining, 

 even in that genus)4 



The detailed descriptions of the skull and teeth given beyond 

 under heads of the several genera of Mephitincv render further 

 account unnecessary here. I would, however, advert to the 

 extraordinarily high rate of variability inherent in the crania 

 of these animals. In other groups, genera might very well be 



* In Melince, the inflation of the bullse is at a maximum for tlie family, 

 tin Melince, and also in MusteJincr, the paroccipitals are close to, or iu con- 

 tact with, the bulla?. 

 t MeJincE, with pm. ~, have a perfectly triangular back upper molar; 



3-3 



4-4 



Lutrino', with quadrate back upper molar, have pm. ^^ 



