AI-K. 1903. NEW SPECIES AND SUBSPECIES OF MAMMALS ELLIOT. 155 



before me, has the gray dorsal stripes conspicuous, and the under 

 parts buff. Neither do these examples exhibit an intergradation 

 between tounisendi and oc/irogenys, or townsendi and hindsi, which 

 last, so far as I am aware, has not been taken beyond the bound- 

 aries of California. The present form varies somewhat in measure- 

 ments, the extremes of the nineteen examples before me being: 

 total length, 245-275; tail vertebrae, 100-124; hind foot, 36-37.5; 

 . ear, 21-24. The differences are probably caused mainly by age, 

 although in some instances the variation in length of the tail 

 determines the differences in the total length. In cranial charac- 

 ters, hindsi has a smaller skull, with narrower and more pointed 

 nasals, narrower palate and rostrum. The skull of T. t. littoralis 

 resembles closely that of T. /. ochrogenys, but is smaller with 

 somewhat larger nasals, and is the intermediate of that sub : 

 species and T. t. hindsi. 



FAM. MURID.E. 

 SUBFAM. CRICETIN.E. 



ONYCHOMYS. 

 Onychomys *macrotis. Sp. nov. 



Type locality. Head of San Antonio River, Lower California, 

 Mexico. 



Geogr. distr. From San Quentin to San Antonio River, 

 Trinidad, and El Alamo, to about 5,000 feet elevation, San Pedro 

 Martir mountains, Lower California, Mexico. 



Gen. char. Size medium, color pale; ears and hind feet long; 

 tail rather long, without white tip; no black spot on ear. 



Color. Above ashy vinaceous, finely lined on dorsal surface 

 and top of head with blackish brown, causing these parts to be 

 slightly darker than the rest of upper surface; sides of body ashy 

 vinaceous; orbital ring black; lips, cheeks, under parts, hands 

 and feet pure white; tail dusky above, white beneath; ears pale 

 grayish brown, outer edge blackish; tuft of white hairs at base 

 of ears. 



Measurements. Total length, 155; tail vertebrae, 55; hind foot, 

 21 ; ear, 20.5. Skull: occipito-nasal length, 26; Hensel, 20; 

 zygomatic breadth, 13.5; interorbital constriction, 4.5; length of 

 nasals, 7.5; palatal arch to alveolus of incisor, 10; greatest width 

 of brain case, n. 



This pale form of Onychomys is remarkable for the great size 

 ?, long; oJ?, ear. 



