A Key to the Genera of North American Mammals 



JJ. Arboreal species, tail long and busliy. 



SCIURUS, 168-176 

 DD. Tooth row nearly continuous, leaving no large gap at the side 



of the jaw. Incisors small and always more than two. 

 % E. Size small (less than seven inches long), fur always drab or 



iron gray, soft and silky; eyes rudimentary. 

 F. Fore feet flattened for digging (Moles) . 



G. A fleshy star on the nose; teeth, i f , c |, p f, m f . 



CONDYLURA, 190 



GG. No fleshy star on the nose. 



H. Tail naked; teeth, i ft, c4, p i, m$. . . .SCALOPS, 188 

 HH. Tail hairy; teeth, i f, c|, p, m f . PARASCALOPS, 189 

 FF. Fore feet normal. 



G. Tail short 1-4 the head and body; teeth, i f f, c, p f, 



m f BLARINA, 180-183 



GG. Tail at least 1-2 the head and body; teeth, i f, c , 



p f, m f SOREX, 184-187 



EE. Size medium or large; eyes well developed. 

 F. Toes webbed. 



G. Hind feet large and very different from the front ones, 

 resembling flippers; teeth, i f , c {, p f , m |, LATAX, 223 

 GG. Feet all alike; teeth, i f, c |, p f, m . .LUTRA, 219-223 

 FF. Toes not webbed.' 

 G. Toes, five on all feet. 

 H. Teeth, i f , c }, p *, m f . 



I. Nose produced into a slender snout ; tail obscurely 



ringed NASUA, 254 



II. Nose not lengthened; tail strongly ringed with 



black and white. 



J. Body thick-set; feet plantigrade. PROCYON, 247 

 JJ. Body slender, weasel-like; feet only partially 



plantigrade BASSARISCUS, 254 



HH. Teeth, if, c }, p f , m J. 



I. Body heavy, bear-like; feet slightly plantigrade. 



GULO, 245 



II. Body more slender; feet digitigrade. 



MUSTELA, 241-245 

 HHH. Teeth, i f , c , p f f, m, \. 



I. Claws long and conspicuous; colors black and white. 

 J. White in two long stripes. .MEPHITIS, 224-229 

 JJ. Markings more complicated. .SPILOGALE, 230 



II. Claws very long and conspicuous; color gray. 



TAXIDEA, 230 



III. Claws short; color brown (often white in winter). 



PUTORIUS, 231-240 

 HHHH. Teeth, i f , c \, p f , m f ; size very large (Bears) . 



I. Color white THALARCTOS, 255 



II. Color, black, brown or tawny. . . .URSUS, 257-264 

 GG. Toes, five in front and four behind. 



H. Toes not retractile; teeth, i f, c |, p f , m f . 



I. Upper incisors lobed CANIS, 277-283 



II. Upper incisors not lobed. 



J. Tail with soft under fur VULPES, 264-275 



JJ. Tail coarse UROCYON, 275-277 



HH. Toes retractile. 



I. Tail very short (4-6 ins.) ; teeth, i f , c \, p f , m {. 



LYNX, 284-288 



II. Tail long, equal to more than half the head and 



body; teeth, i f , c , p f , m | . . FELIS, 288-293 



300 



