MAMMALS OF THE MEXICAN BOITN«ARY. 430 



Description -This slight geographical race of Peromyscus ereniicus 

 differs from the tvj^ical form in being larger, darker with brigliter 

 ochraceous coloration, and smaller ears. From the varied character 

 of its liabitat this subspecies is less uniform in size, coloration, and 

 proi)ortions than the other forms of eretnicus. In specimens from the 

 strip of country" between the ]\[imbres Valley and the San lAiis Afoim- 

 tains the ear is decidedly smaller than that of typical errmicu.'^. West 

 of the San Luis ]\Iountains the ear increases in size and the coloration, 

 as a ru\o, is darker. In the canyons at the head of the Yaqui River a 

 small, dark-colored phase was found which may prove to be worthy of 

 separation as a subspecies if further differentiated in the lower Yaqui 

 River tract. In this connection I have examined two specimens 

 from Oposura, Sonora (Nos. 8816 and 8817, collec- 

 tion of the American JNIuseum of Natural History, 

 New York), forwarded to me by Dr. J. A. Allen. 

 These are the darkest ones seen, and somewhat 

 larger than two from Guadalupe Canyon (Nos. 

 58878 and 58879, IJ.S.N.M.) on the International 

 Line at the head of the Yaqui. These four are 

 miich like P. tihuronensis , a species inhabiting 

 Tiburon Island, in the Gulf of California, near the 

 mouth of the Yaqui River. The skull is shown 



ni rig. 1U4. ... ^ l^iG. 104.— Peromyscus 



Habits and local distribution. ^-When camped eremicus anthonyi. 

 near Wheatfield, Arizona, October 21, 1884, I set f°!'f'''' '""'^ "'^ 

 out in company with Gen. George Crook in search 

 of Whitne}^ owls {MicropaUas whitneyi). Several giant cacti were 

 chopped down, and in a hole in one of them we found a soft nest 

 containing two of these mice, one of which, an old femal?, was 

 caught. On the following day we found more of them under old 

 logs of Cottonwood in a camp on Tonto Creek. It lived and built 

 nests in closets and drawers of my quarters at Fort Verde,, in Cen- 

 tral Arizona. On the Mexican Boundary Line it was first taken at 

 Monument No. 15, where it was restricted to bush}'^ places and rocky 

 buttes, none having been taken on the level sandy ground where 

 most of our trapping was done. This form of the desert mouse con- 

 tinued v;estward in abundance in similar situations to the Sonoyta 

 Valley of Sonora. It was sometimes found with Peromyscus boylii 

 pinalis. 



