SQUIRRELS OF MEXICO AND CENTRAL AMERICA 99 



Sciuriis astiians Alston, Biol. Cent. -Am., Mamm , pp. 132-133, 1880 (part : 



Costa Rica and Panama). 

 Sciiirus astnans }toffma7itii h.\x.^-^, Bull. Am. Mus. Nat. Hist., N. Y., in, pp, 



206-207, 1891 ; Ibid., IX, p. 35, 1897 ; Alfaro, Mamiferos de Costa 



Rica, p. 31, 1897. 



Type locality. — Costa Rica, Central America. 



Distribution. — Humid tropical forests of Costa Rica, south to Val- 

 ley of upper Cauca River, Colombia. 



Characters. — Size similar to that of ^S". cestuafis^ but color much 

 darker and more rusty brown on back, more ferruginous red on under- 

 parts, and tail heavily w^ashed with bright ferruginous. Tail broad 

 and flat ; pelage soft and rather thin. 



Color. — Entire upperparts, including top of nose and base of tail, 

 finely grizzled dark yellowish or rusty brown; top of head and middle 

 of back usually a little darker than sides and sometimes blackish ; out- 

 side of legs and feet similar to back but often more yellowish or rusty ; 

 ears usually a little darker rusty than top of head, with small basal 

 patch of dingy fulvous or dull rusty ; sides of head more yellowish or 

 rusty than back ; ring around eye dark buffy or sometimes rusty yellow- 

 ish ; chin and throat dull buffy yellowish, sometimes suffused with 

 rusty; rest of underparts varying from dull rusty buff to deep ferrugi- 

 nous ; tail above black, heavily washed with bright ferruginous, some- 

 times becoming paler but always strongly ferruginous ; below with 

 broad median area of grizzled black and dark yellowish brown, bordered 

 with black and edged with ferruginous. Hairs on back, black with 

 narrow sub-terminal rings of buffy or rusty yellow, sometimes with 

 similar sub-basal rings. 



Variatiojz. — The amount of variation seems to be comparatively 

 small. Specimens from Talamanca and Santa Clara in eastern Costa 

 Rica are darker than those from elsewhere in that country. Some 

 from the valley of the upper Cauca River, Colombia, are a little paler 

 or more olivaceous than Costa Rica specimens, but others from the 

 same district are indistinguishable. 



Measurements. — Averages of four adults from eastern Costa Rica : 

 total length 426.6; tail vertebrte 187; hind foot 54.3. 



Cranial characters. — Premolars \. Skull (pi. I., fig. 7) rather 

 broad, braincase arched and inflated over interparietal region and con- 

 stricted posteriorly, so that the occipital region is a little drawn out ; 

 audital bullae small and rounded. Five adult skulls from central and 

 eastern Costa Rica average: basal length 43.2; palatal length 23.3; 

 interorbital breadth 17; zygomatic breadth 31.3; length of upper 

 molar series 9. 



