NO. 2057. 



THE GRASSHOPPER MICE—H0LLI8TER. 



455 



nearly equal; anterior cusp of m} more broadened transversely, in 

 unworn condition plainly divided at summit into two or three cusp- 

 lets; 7n} narrow and elongated; m^ smaller, much reduced, the gi*eatest 

 diameter transverse, the crown surface usually only one-sixth to 

 one-fourth that of m^ (rarely nearly one-third) ; owing to the length- 



FiG. 3.— Distribution oe the Subspecies of Onychomys torridus. 



1. O. t. torridus. 



2. O. t. perpallidus. 



3. O. t. pulcher. 



4. O. t. longicaudus. 



5. O. t. Claras. 



6. O. t. tularensis. 



7. O. t. ramona. 



8. O. t. macrotis. 



9. O.t. 



10. O. t. canus. 



11. 0. t. surrulus. 



is almost invariably more 



ening of m^ and the reduction of m^, 

 than half the length of the tooth row. 



Geographic distribution. — Southwestern United States and northern 

 and central Mexico. From the deserts of Nevada and southeastern 

 California and the San Joaquin Valley, south into Lower California 

 and to Aguas Calientes and San Luis Potosi, Mexico. Eastward 

 across southern Arizona and New Mexico to the Pecos Valley in 

 Texas (see fig. 3). 



