36-1 Univt rsity of California Publications in Zoology [Vol. 10 



San Bernardino and San Jacinto Mountain region is reached. 

 From those points south through San Diego County, there is 

 a distinct increase. The matter of size, therefore, fails to argue 

 for a race dispar; but it is usable as a fairly good average char- 

 acter for the distinguishing of a form in extreme southern Cali- 

 fornia. It is of further note, however, that even then, the wide 

 range in individual variation destroys the usefulness of this as 

 a specific criterion in a number of individual instances. For 

 example a male from San Mateo County (no. 3862) measures, 

 Length 21] mm., tail 1-20, hind foot 27, this being coincident with 

 the largest of the specimens from "Witch Creek. San Diego County 

 (male do. 2983). 



(4i Cranial features. — As with general size of body there is 

 a slight increase in cranial ma.ss in the series from extreme south- 

 ern California. But we are unable to discern proportional differ- 

 ences anywhere. The features mentioned by Osgood in this con- 

 nection are: size ill' mastoids, degree of arching of cranium, 

 mastoid width, interorbital width, width of nasals and degree 

 of emargination of Eronto-nasal sutures. In all these respects 

 there is much individual variation but none that is clearly cor- 

 related with geographic areas. 



To summarize, there is nut. from our material, warrant for 

 recognition of a race dispar as distinct from californicus. This 

 possibility was anticipated by Osgood (11)04. p. 128) in his 

 remarks when describing ochrus, where he says: "/'. c. dispar 

 is itself slightly paler than calif vrnicus, but the principal reason 

 t'ni' recognizing it is its larger size and cranial characters. Should 

 these cranial characters prove inconstant on the acquisition of 

 lamer series el' true californicus, dispar would fall as a synonym 

 of californicus. " 



As a further conclusion there now appears no justification for 

 considering femoralis as of more than subspecific status, its 

 relationship to be best expressed in the trinomial. Perognathus 

 californicus femoralis. The main, if not the only, character of 

 this race as compared with californicus is its large size, particu- 

 larly of hind foot and ear. By our study, the range of the 

 formerly recognized dispar becomes divided between that of 

 californicus and that of femoralis, the range of the latter being 



