1913] Grinnell-Swarth : Birds ami Mammals of San Jacinto 351 



the same distance due south up over the northwestern spur from 

 the peak. And one (no. 2288) is from Vallevista, 1800 feet, 

 down at the south base of this spur. It would appear that the 

 species occupies the arid Upper Sonoran zone on the San Gor- 

 gonio and San Jacinto Valley sides of the mountains, possibly 

 invading down into Lower Sonoran locally, but not as far down 

 into that zone farther east, as at Palm Springs, where a totally 

 different species occurs, Thomomys perpallidus. 



The specimens of Thomomys cabezonae from Snow Creek and 

 Schain's Ranch differ in no important particular from topo- 

 types of the species. But the lone example from Vallevista, a 

 male, young adult, is very slightly more reddish in color. Other- 

 wise, however, it departs towards no other species. Examination 

 of the map, and consideration of the uninterrupted and almost 

 uniform conditions extending over the hills between Cabezon 

 and San Jacinto, makes the continuity in range of this species 

 between the localities represented quite probable. 



In addition to the above, there are at hand three gophers 

 (nos. 16393-16395) taken at Whitewater Ranch, which lies a 

 mile or so north of Whitewater Station. They were obtained by 

 Mr. II. E. Wilder, December 17, 1911," and presented by him 

 to the Museum. These are closely similar to topotypic cabezonae. 

 and indicate the occurrence of this form along the northern wall 

 of San Gorgonio Pass, possibly invading the southern foothill 

 region of the San Bernardino Mountains, as it does the northern 

 foothills of the San Jacintos. 



The query arises as to the relationships of cabezonae with 

 the other species of gophers of the general region. Our material 

 has been gone over with this point particularly in view, without 

 our ascertaining anything definitely. This failure is due chiefly 

 to lack of appropriate material from a critical series of localities. 



In a very general way the material at hand seems to indicate 

 that cabezonae is more nearly related to nigricans than to either 

 perpallidus or perpes. It is thus possible that cabezonae will 

 turn out to be a pallid, and otherwise distinguished, desert race 

 of nigricans, with very much the same relative ranges and char- 

 acters as Perognathus f. pallidus and P. f. fallax, and also cer- 

 tain other rodents. 



