MAMMALS OF THE MEXICAN BOUNDARY, 



431 



little shorter in the iiortJiern specimens; but I can discern no other 

 difference of importance. The alleged difference in the form of the 

 frontal bones referred to by Mr. Rhoads^' is due to difference of age 

 in the specimens examined. The skull and teeth of P. c. insignis are 

 shown in figs. 97 and 98. 



Ilahits and local distribution. — This large mouse is an inhabitant of 

 rocky places where bushes and oak trees grow. Young in the gra}' 

 coat were obtained at Tecate, in Lower California, June 28, 1894; and 

 a female, containing two large young, was taken the same day. 



Measurements of 14 specimens of Peromyscus califomicus irbsignis. 



PEROMYSCUS EREMICUS (Baird). 

 "WESTERN DESERT MOUSE. 



Hesperomys eremicus Baiuu, Mum. N. Am., 1S57, pp. 479, 480 (original description); 



Rep. U. S. and Mex. Bound. Surv., II, Pt. 2, Mam., 1859, p. 44. 

 Peromyscus eremicus, Allen, Bull. Am. Mus. Nat. Hist., VII, p. 226, June 29, 1895. — 



Miller and Reiin, Proc. Bost. Soc. Nat. Hist., XXX, No. l,Dec. 27, p. 72 (Syst. 



Results Study N. Am. Mam. to close of 1900). 

 [Peromyscus^ eremicus, Elliot, Field Col. Mus., Zool. Ser., II, 1901, p. 136 (Synop. Mam. 



N. Am.); IV, 1904, p. 191 (Mam. Mid. Am.). 



Type-locality. — Old Fort Yuma, San Diego County, California. 

 (Co-types in the U. S. National Museum.) 



Geographical range. — -Tropical and lower wSonoran zones of the 

 Western Desert Tract. 



a Proc. Acad. Nat. Sci. Phila., 1895, p. 34. 



