XVIII. 



Grasshopper-mouse, Calling-mouse, Short-tailed Deer- 

 mouse, or Missouri Mole-mouse. 



Onychomys leucogaster (Wied). 



(Gr. Onychomys, from Onychos, a claw, and mys, a mouse, hence 'claw-mouse,' be- 

 cause its claws are so large compared with those of other Mice; Gr. leucogaster, 

 from leucos, white, and gaster, belly.) 



Hypudaus leucogaster WiED, 1 841, Reise, Nord. Amer., II, 



p. 99. 

 Onychomys leucogaster Baird, 1857, Mam. N. A., p. 459. 

 Type Locality. — Clark, Clark County, South Dakota. 



The genus Onychomys (Baird, 1857) comprises Mice 

 which have the general form of Microtus combined with the 

 colours of Peromyscus, the soles of the feet are densely furred 

 and have only 4 (instead of 6) tubercles; the tail is less than 

 half the head and body. The front claws and feet are highly 

 developed for digging. 



I— I 2—'Z 



The teeth are: Inc. ; mol. ^^^ = 16 



In addition to these generic characters the Grasshopper- 

 mouse has: 



Length, about 6^ inches (160 mm.); tail, if inches size 

 (45 mm.); hind-foot, f inches (23 mm.). 



All above soft grayish-brown, sprinkled over with fine colour 

 black hairs; on the sides and rump this shades into orange 

 and buff, and ends abruptly against the creamy white of all the 

 under parts; the colour is darkest on the lower back, but there 

 is no dorsal band, as in Peromyscus; feet, white; tail, gray- 

 brown above, white below, except on tip, which is all white. 



483 



