SCIURIDJE— TAMIAS ASIATICUS AND VARIETIES. 799 



more strongly differentiated. Specimens from Northern California show a 

 strong resemblance to specimens from the Rocky Mountains near the forty- 

 ninth parallel, and from the Bitter Root region ; in some cases the white 

 edging of the tail in the Californian form being the only really distinctive 

 feature. Further southward still, in Southern California, the general colors 

 become still paler and the dorsal surface grayer. The tail, however, retains 

 the greater blackness and whiter edging which characterize the toivnsendi 

 type. The desert region of the Gila River presents also a quite peculiar type, 

 in which the general color of the dorsal surface becomes of a nearly uniform 

 ashen-gray, with all the stripes obsolete except the middle one. Very few 

 specimens of this form have as yet been received, and from finding occa- 

 sionally specimens from other regions, and even also in another species 

 (7. striutus), with the stripes but faintly developed, it seems possible that 

 this form may be scarcely entitled to varietal recognition. I have seen speci- 

 mens from the Great Salt Lake Valley and from Colorado with all the stripes 

 except the central obsolete. Field observers, however, refer to it as a com- 

 mon form in Arizona and neighboring regions. Iu its rather full, bushy, 

 white-edged tail and rather large size, it evidently finds its nearest ally in 

 the Pacific-coast type, of which it is probably the desert representative. 

 No. 3385, from Fort Defiance, New Mexico, however, agrees with var. qua- 

 drivittatus, except in the obsolescence of the stripes, the sides being strongly 

 fulvous. 



According to von Schrenck, the Asiatic animal presents everywhere great 

 constancy of coloration. Even those of the partly open prairie-country of 

 the Ussuri, he affirms, differ not in the slightest degree (zetgen jedoch nicht 

 die geringste Verschiedenheit) from those of the coniferous forests about the 

 mouth of the Amur River. He further adds that a specimen brought by 

 Temminck from Japan was not in any way different from those from the 

 Asiatic continent.* So far as can be at present determined, the Siberian 

 animal differs far less from that found in boreal America than does the latter 

 from the form found in the Upper Missouri Bad Lands, the mountains of 

 Colorado, or the region around Puget's Sound, or than these several strongly 

 marked but demonstrably intergrading forms do from each other. 



From the subjoined tables of measurements, it will be seen that the vari- 

 ation in size among American specimens ranges from an average length of 



* Amur-Lunde, pp. 124, 125. 



