ANALYSIS OF GENERA OF MUSTELID^E. 



SCHEDULE OF DIFFERENTIAL CHARACTERS OF THE NORTH 

 AMERICAN GENERA. 



Various characters hy which the subfamilies and-genera are differentiated are ex- 

 hibited in the foUoxving schedule: — 



3-3 

 Dental formula : I. o_3, 



3-3 

 ^- 3-3' 



C. ^ 



3-3 

 3-3- 



I. .T^, C. 



M. 



3-3 

 3-3' 

 3-3 



2-2' 



1-1 

 1-1' 

 1-1 

 i' 

 l-l 

 1-1' 

 1-1 

 2-2' 

 1-1 

 1-1' 

 1-1 

 1-1' 



Pn.- 4=4' 



Pm. 



3-3 

 3-3' 



M. 



M. 



38. 



^-''-34 



2-2 3-3 



Pm. normally ttj-,, sometimes .j^, 



Pm. 



Pm, 



16 



4-4 

 3-3' 

 3-3 

 3-3 



= 32 or 34.... 

 1-1 18 



M. 



M. 



2-2-18-^"- 



1-1_16 



•^-2-16-^^- 



PjMT. and M. normal— angular, trenclianti or acute 



abnormal — rounded, blunt, tuberculous 



Back upper M. quadrate, transverse, much wider than long 



about as wide as long 



triangular, the hypothenuse postero-esterior 



irregularly oval ; all corners rounded off 



Back upper Pm. strictlj^ sectorial, linear, with small anterior interior 



cusp - . - . 



triangular, owing to size of the in- 

 ner ledge 



resembling the back upper M 



Upper Pm. 4-4, the anterior one comparatively well developed 



minute, crowded out of line 



3-3, the anterior one comparatively well developed 



or 2-2; when 3-3, the anterior very minute 



Lower L 3-3, the usual carnivorous formula 



2-2, the inner pair lacking 



Lower sectorial without obvious inner tubercle of middle lobe. 



with slight but evident inner tubercle 



with strongly developed inner tubercle 



Eostrum of skull so short that root of zygoma is nearly or quite op- 

 posite fore end of nasal bones 



moderately produced ; root of zygoma more nearlj- 



opposite hind end of nasals 



Brain-case comparatively compressed backward, little broader be- 

 hind than before, with straightish or little convex 



lateral outline 



widened backward, with quite straight lateral outlines., 

 much widt^ned backwards and swollen outward, with very 



convex lateral outlines 



Frontal region very short, broad, flat on top 



lengthened, narrowed, very convex transversely 



Bony palate ending opposite back upper molais 



produced back of the molars, but not Lalf-way to end 



of pterygoids -' 



produced far back of the molars — half-way or more to 



ends of pterygoids 



Postorbital processes moderate, slight or obsolete 



strong, transverse, acute 



Anteorbital foramen bounded above by slender maxillary process, 

 large, subtriangular, or oval, presenting downward-forward 



Mustelidte. 



