1913] Grinnell-Swarth : Birds and Mammals of San Jacinto 359 



These localities are all within the Upper Sonoran zone; Ban- 

 ning and Dos Palmos Spring are at the extreme lower edge of this 

 zone, where occur also many Lower Sonoran elements; Ken- 

 worthy is close to the upper limits of Upper Sonoran. It is of 

 note that in this latter locality all of the kangaroo rats taken 

 were from the sage-brush flat on the floor of the valley, none 

 being found in the chaparral-covered hills on either side. One 

 example here was found freshly caught at 5 p.m. on June 4, 

 indicating unusual diurnal activity. 



"We have subjected the above-specified series to close scrutiny, 

 both inter se, and in comparison with agiUs from the Pacific 

 slope of Los Angeles County. As far as we are able to discern, 

 there are no good characters existing to warrant separation from 

 agilis; neither can we detect differences correlated with the desert 

 and Pacific slopes respectively. The examples from Banning are 

 exactly like those from Kenworthy ; also the two from Dos Palmos 

 Spring are indistinguishable from specimens from Kenworthy. 

 As in the case of certain other rodents found at Dos Palmos, the 

 presence of Perodipus agilis there may be accounted for as an 

 extreme encroachment down into the edge of the desert area of 

 a Pacific slope form. As noted elsewhere an extraordinary mix- 

 ture resulted. 



Perodipus cabezonae C. H. Merriam 

 Cabezon Kangaroo Rat 



But one example of five-toed kangaroo rat was secured in the 

 vicinity of Cabezon, the type locality of Perodipus cabezonae. 

 This specimen is an adult male, no. 1322, taken May 11. It 

 accords closely with Merriam 's description. As compared with 

 agilis, it is more yellow, with paler face, and hind feet with 

 dusky instead of black soles. In size it is smaller, with especially 

 short tail, measuring: total length 274, tail vertebrae 160, hind 

 foot 40. 



No other Perodipus secured by us in the San Jacinto region 

 is referable to this form, those even from Banning, only six 

 miles farther up through San Gorgonio Pass, being distinctly 

 different. It is hazardous for us even to conjecture relationships 

 and range upon such inadequate evidence, save that Cabezon is 



