MAMMALS OF THE MEXICAN BOUNDARY. 



379 



under surface, feel . and end of tail, white Average measurements of 

 two adull females: Length, 154 mm.; tail vertebrae, 56.5; ear Prom 

 crown, L5; lengthof hind foot, 21.3. Skull (fig. 66), 26.3 by L3.5. 



A young male (No. 60815, U.S.N.M.), aboul two-thirds grown, 

 taken at Seven Wells, on the Colorado Desert, in Lower California, 

 measured 128 mm. in length, with the tail vertebrae ■'>'», ear from 

 crown 1 I, and hind foot '21. Above, it is smoke gray. The ear shows 

 a distinct dusky spot of mouse gray, and t he terminal t hird of t he tail 

 is all white. 



Measuremt nts of 5 specimens Onychomys torridus perpallidus. 



a Contained 4 large fetuses. 



b Type. 



ONYCHOMYS TORRIDUS RAMONA (Rhoads). 

 RAMONA GRASSHOPPER MOUSE. 



Onychomys ramona Rhoads, American Naturalist, XXVI I, p. 833, Sept., 1893 1 original 

 description). — Miller and Rehn, Proc. Bost. Soc. Nat. Eist., XXX. No. I. Dec. 

 27, 1901, p. 67 (Syst. Results Study X. Am. Main, to close of L900). 



[Onychomys] ramona, Elliot, Field Col. Mus., Zool. Ser., 11, 1901, p. 121 (Synop. 



Mam. X. Am. ). 

 0[nychomys] ramona, Elliot, Field Col. Mus., Zool. Ser., IV. 1904, pp. L65, 167 (Mam. 

 Mid. Am. i. 



Descri ptiou. Size of typical Onychomys torridus but very much 

 darker in color. Proportions about the same as those of torridus. 

 Upper surface drab, tinged with cinnamon on sides, and much mixed 

 with black on top of head and vertebral area ; lanuginous tufts at base 

 of ear soiled grayish white; ears blackish, edged with white apieally: 

 upper side of tail blackish nearly to the tip; whiskers mostly black: 

 under surface, feet, and extreme tip of tail, white. Average measure- 

 ments of two adults, male and female: Length, 1 VA mm.: tail verte- 

 brae, 51.5; ear above crown, 14; length of hind foot, 2').."). Skull, 25 

 by 13. 



Two gray-pelaged young, collected by Mr. Holzner, May 21 and 25, 

 at the foot of the Santee Mountains, San Diego County, California, 

 have the upper surface mouse gray, and the ears nearly black. They 

 are the darkest specimens seen of this species. 



