88 Nelson — Two New Subspecies of North American Mammals. 



on upper side of tail the rufous heavily overlaid by a zone of black and latter 

 covered by a strong outer wash of whitish ; tail averaging broader and 

 more bushy than in socialis; underparts of body and under side of legs 

 deep, rich rufous ; base of ears behind with a bright patch of wliite ; a 

 forward extension of nape patch surrour-ds the eyes ; top of head in front 

 of nape patch darker and more iron gray than back ; cheeks and under 

 side of head whitish. 



ShdL — Similar to that of socialipi. 



Measurements of ti/pe. — Total length, 52(); tail vertebne, 27o; hind 

 foot, 69. 



Remarks. — The present form is based on a series of seven specimens, 

 all frf)m the type locality. So many squirrels have been described from 

 Mexico that it may appear superfluous to name another. However, the 

 l^resent series agree so uniformly in their much paler colors when com- 

 pared with the large series of typical socialis in the Survey collection 

 that they evidently represent a well-marked local form. The absence of 

 a rrnn]) patch at once distinguishes them from cocos which reaches a point 

 on the coast of Oaxaca not far to the northward. To the south socialis 

 occupies the coast country about Salina Cruz, Oaxaca, while a specimen 

 collected in the mountains half a day's journey on horseback directly in- 

 land from Puerto Angel is evidently referable to socialis. This leaves 

 littoralis with a restricted distribution. It is an intergrading form be- 

 tween cocos and socialis and nearly as pale as the former, l)ut has lost the 

 rufous rump patch characterizing that subspecies. 



