70 NELSON 



rusty rufous, while the two others are washed with rufous except a 

 grizzled gray band about 4 inches broad across the belly. The median 

 area on the lower surface of tail is sometimes broad, sometimes merely a 

 narrow line (the black border increasing in width as the other de- 

 creases) and varies from rusty ferruginous to yellowish brown. 



Measurements. — Average of five adults from type locality : total 

 length 506.2 ; tail vertebrae 256; hind foot 68.2 



Cranial characters, — Premolars \. Skull a little shorter than that 

 of griseojlavus but scarcely distinguishable from the latter or from 

 that of kS. aureogaster. Five adult skulls from the type locality aver- 

 age : basal length 50.9; palatal length, 26.6; interorbital breadth 

 19. 1 ; zygomatic breadth 34.3 ; length of upper molar series 11.4. 



General notes. — The squirrels taken in the oak forest between 9000 

 and 10,000 feet altitude on the mountains at Todos Santos, Guatemala, 

 are intermediate between chiapejisis and true griseojiaviis. Those 

 taken at Calel, Guatemala, are more yellowish brown and much closer to 

 griseojlavus. A specimen from the arid subtropical canyon at Nenton, 

 Guatemala (below 3000 feet) , and two others from similar localities near 

 Tuxtla, Chiapas, seem to indicate a direct gradation, in this intermediate 

 region, between S. griseojlavus chiapensis and S. socialis. Unfortu- 

 nately our series from intermediate points is too limited to satisfactorily 

 decide this point. Surprising as it may appear, the differences be- 

 tween griseojlavus chiapensis and socialis are not greater than those 

 between the latter and S. socialis cocos. 



Habits. — The Chiapas squirrel feeds upon both acorns and pine 

 seeds, moving from one part of the forest to another with the season. 



Specimens examined. — Twelve : all from the type locality. 



SCIURUS YUCATANENSIS Allen. Yucatan Squirrel. 



Sciurus carolifiensis var. yucatanensis Allen, Mon. N. Am. Rodentia, pp. 



705-706, Aug., 1877 ; Bull. U. S. Geo). Survey; Terr., iv, p. 879, 1878. 

 Sciurus caroline-nsis Alston, Proc. Zool. Soc. London, 1878, pp. 658-659 ; 



Biol. Cent. -Am., Mamm., pp. 124-125, June, 1880 (part: specimens 



from Yucatan). 

 Sciurus yucatanensis Allen, Bull. Am. Mus. Nat. Hist., N. Y., ix, pp. 5-7, 



1897. 



Type locality. — Merida, Yucatan, Mexico. Cotypes nos. 8';o2- 

 8503. U. S. National Museum. 



Distribution. — Arid tropical forests of peninsula of Yucatan. 



Characters. — Back dingy, coarsely grizzled gray; belly white; 

 l^elage coarse and harsh but not bristly ; thin ear tufts sometimes pre- 

 sent, yellowish white ; tail rather full. 



