58 



NORTH AMERICAN FAUNA. 



[no. 39. 



Lower California: Aguaji de las Fresas, 2; Euseiiada, 6; Ensenada (canyon 20 

 miles east), 1; Fresnal, 1; Hanson Lagiina, 11; La Gmlla (at 7,000 feet alti- 

 tude), 13; La Huerta (Hanson Lagima Mountains), 1; Mattomi, 1; Milquatay 

 Valley, 2; Nachoguero Valley, 4; Parral, 5; Pinon (west slope San Pedro 

 Martir Mountains), 3; Rancho la Progresa, 5; Ranclio Santo Tomas (12 miles 

 south of La Grulla), 3; Rancho Viejo (15 miles south of Alamos), 5; Rosarito, 

 2; San Antonio, 3; San Francisquito, 2; San Pedro Martir Mountains, 11; 

 San Quintin, 14; San Telmo, 18; San Ysidro Ranch, 4; Santa Eulalia, 7; 

 Santa Rosa, 1; Santo Tomas, 18; Socorro, 2; Tecate Valley, 2; Trinidad 

 Valley (northwest base San Pedro Martir Mountains), 2; Vallecitos, 6; Yubay, 

 4 (not typical). 



THOMOMYS BOTT^ PUERTO Grinnell. 

 La Pubrta Pocket Gopher. 



Thomomys nigricans puertse GriimeU., Univ. of Cal., Publ. ZooL, XII, 315, Nov. 21, 1914. 



Type. — Collected at La Puerta (Mason's Ranch, 5 miles west of Val- 

 lecitos, at the lower end of La Puerta Valley), San Diego County, Cali- 

 fornia, by F. Stephens, May 31, 1909. Type specimen in Mus. Vert. 

 ZooL, Univ. of California. 



Distribution. — ^La Puerta and San Felipe Valleys, Cal. (fig. 6). 



Characters. — In size, proportions, and cranial characters, very 

 similar to nigricans, but much paler in both summer and winter 

 pelage; considerably brighter than cabezonse. 



Color. — Summer pelage: Upperparts pale ochraceous-tawny, be- 

 coming darker along median line of back; ears and postauricular spot 

 black; nose and face brownish or dusky; underparts pale or bright 

 cinnamon; feet and tail buffy or soiled whitish. Winter pelage: 

 Duller and more grayish, fading to pinkish- or vinaceous-salmon in 

 bright-colored individuals. 



Slcull. — Not readily distinguishable from that of nigricans from the 

 surrounding chaparral slopes. 



Measurements. — Type ( young ad.): Total length, 203; tail verte- 

 brae, 80; hind foot, 28. SlcuU (of type) : Basal length, 32; nasals, 12; 

 zygomatic breadth, 21.2; mastoid breadth, 18; interorbital breadth, 

 6; alveolar length of upper molar series, 7. 



Remarlcs. — The series of 43 specimens in the Museum of Vertebrate 

 Zoology labeled La Puerta were collected by F. Stephens, and Grinnell 

 says, ''According to his field notebook, the majority were caught in 

 cultivated land on Mason's Ranch, which is located at the lower end 

 of La Puerta Valley. Others, however, were taken on surrounding hill- 

 sides."^ The 43 specimens divide readily into 21 of the present pale 

 form and 22 of the typical dark-colored nigricans. These I assume 

 represent a pale desert form from the valley bottom where creosote 

 bush, mesquitCj and cactus indicate extreme arid Lower Sonoran 

 conditions; and typical nigricans from the Upper Sonoran chaparral- 



1 Univ. of Cal. Pub. ZooL, XII, 315, Nov. 21, 1914. 



