MURID^ 101 



Mus musculus Linn. (Little Mouse.) 



COMMON MOUSE. 



Tail longer than head and body ; above yellowish brown 

 thickly mixed with black hairs; below ashy brown; feet brown; 

 tail dusky, sometimes lighter below. 



Length about i6o mm. (6.30 inches) ; tail vertebrae 82 

 (3.25) ; hind foot 18 (.70). 



Introduced from Europe. Now found in most old settle- 

 ments in the State. Principally frequent houses and other build- 

 ings, from which they drive the less objectionable native mice. 



Subfamily Cricetinae. 



Skull short and moderately broad; rostrum rather short; 

 nasals projecting beyond premaxillaries; enlargement at root 

 of lower incisor near base of condylar process greatest on outer 

 surface; tip of angular process of low^er jaw below plane of sum- 

 mits of lower molars ; notch between tip of angular process and 

 condyle shallow; molars rooted, tuberculate, the tubercles in two 

 series; palate ending opposite end of molar row\ 



Genus Onychomys Baird. (Claw — mouse.) 

 Upper incisors broad, causing a broadening of the rostrum 

 at their roots; posterior molars above and below much smaller 

 than the others ; nasals long, wedge shaped posteriorly ; coronoid 

 process of lower jaw long, slender, curved backward; fore feet 

 large with long claws; tail thick, blunt, short, about half as 

 long as head and body. 



Onychomys torridus ramona Rhoads. (Torrid; for 

 "Ramona.") 



SAN BERNARDINO GRASSHOPPER MOUSE. 



A broad indefinite dorsal band from nose to tail dark brown ; 

 sometimes blackish; sides reddish bistre; below white, this color 



