320 



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



is mixed black and dull brownish yellow or whitish, which tint shows almost uniformly beneath 

 and broadly on the margin and tip of the tail. When the tail is flattened at the tip it shows 

 distinctly a very broad bar of black within the light margin, and another narrow bar of the 

 same half way between this and the extreme base, which is also black. There are thus exterior 

 to the dark base two bars of black and three of whitish, the basal half of the hairs being light 

 colored, with a narrow dark bar in the centre, as also at the base ; the terminal half black and 

 light colored, about equally divided, except towards the tip where the black is more extended. 

 Specimens vary, as already stated, in the tint of the ground color above and in other charac 

 ters, the length of hair on body and tail, &c. Sometimes the dusky base to the caudal hairs is 

 obsolete. In one (231) the hairs at the tip are very long, over two inches ; but this seems 

 abnormal. Many of these differences are, however, doubtless those of season. 



This species can be readily distinguished from its nearest allies, S. I'3-lineatus and S. spilo 

 ttoma. The ground color of the former species is darker, and the alternating stripes and lines of 

 spots are unmistakably different ; its tail is shorter and less bushy, while the hairs are dull 

 whitish or yellowish white, with only one median broad bar instead of two. In the skulls 

 there is a very close resemblance. From S. spilosoma it differs by its more acute muzzle, the 

 much greater distinctness of spots, more conspicuous ears, longer and fuller tail, its hairs 

 having two bars of black instead of one bar, which at the tip extends to the very base. The 

 skulls of the two are very different, in the much shorter and more convex form of the latter, &c. 

 In Captain Pope's collection are several specimens from the Pecos river, which may be con. 

 sidered as the most northern limit yet recorded for the species. They are duller than those from 

 the Rio Grande, the fur being in very old and ragged condition, probably just about to be 

 replaced by new. 



This is probably the species to which Erxleben gave the name of Sciurus Mexicanus in 1777. 

 It was first accurately described by Lichtenstein from a specimen collected near Toluca. How 

 much further south it extends I am unable to say. The Rio Grande appears to be nearly its 

 northern limit. 



List of specimens. 



Eye dark brown ; skin of feet white. 



' Skull 1.75 -f 1.03 inches. 



