298 



U. 8. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



On the fore foot the second'toe, with its claw, is longest ; the third, little shorter ; the inner 

 next longest, not much exceeding the outer. The thumb is very minute. The three middle 

 hinder toes are longest, the central one a little longer than the rest ; the others considerably 

 shorter, with the claws not reaching to the claws of the rest ; the outer longer than the inner. 



(No. 2468.) 



In all the specimens from the Upper Missouri and Yellowstone rivers 1 there is a constant 

 difference from the preceding description in the much greater lightness of color. The dark 

 stripes have much less black in them, excepting the central one, which is usually more distinct. 

 They are also smaller and the tail longer. A specimen from the Black Hills (1908) is inter 

 mediate in shade between the Yellowstone and the much darker Kocky Mountain specimens, 

 especially 2468 from the Sangre del Cristo Pass, a locality very near that of Say's original 

 specimen. 



As previously mentioned, the Tamias pallasii of Europe has close relationships to T. qiiadri- 

 vittatus, although they are readily distinguished on comparison. The former species is 

 considerably the larger, in fact, fully twice the size, as shown by the accompanying table of 

 measurements. 2 The tail is fuller and more bushy. The dorsal stripes are more distinctly 

 black and broader, and have no border of brownish, being immediately in contact with the 

 reddish white narrower intervals. There is none of the rusty color of the side seen in 

 T. quadrivittatus, this being replaced 'by a light brownish yellow. The tail is also much 

 lighter colored, the hairs being rusty yellow, tipped with grayish white, and with a broad 

 subterrainal annulation of black. 



The common chipping squirrel (Tamias striatus) is easily distinguished by the fact that the 

 spaces between the two outer dark stripes are alone whitish ; those on each side the dorsal line 

 being mixed like the back. The stripes do not reach to the root of the tail ; the hind part of 

 the back being dark ferruginous. 



1 " I first saw this sprightly squirrel at the mouth of the Yellowstone, and encountered it frequently in our passage along 

 this river. It is abundant in the Bad Lands, preferring rocky ledges, and living on the leaves and seeds of the common 

 sage, (Artemisia frigida ? and tridentata.) It is occasionally seen about heaps of flood wood along the river. Its movements 

 are much like those of the common ground squirrel, and its note differs only in not being so loud. They never sit and 

 chatter, but give two or three chirps as they run along to their hole." Dr. F. V. Hayden, in letter, 1855. 



Tamias paUasii, (measurements.) 



