72 NELSON 



Schirus hypopyrrhus Alston, Proc. Zool. Soc. London, pp. 662-664, 1878 

 (part); Allen, Bull. U. S. Geol. Survey Terr., iv, pp. 881-882, 1878; 

 (part); Alston, Biol. Cent. -Am., Mamm., pp. 123-131, 1880 (part: 

 specimens from interior of Costa Rica) ; Allen, Bull. Am. Mus. Nat. 

 Hist., N. Y., Ill, p. 206, 1891 ; Bull. Am. Mus. Nat. Hist., N. Y., ix, p. 35, 

 1897 ; Alfaro, Mamiferos de Costa Rica, pp. 30-31, 1897 (part : speci- 

 mens from eastern Costa Rica), 



Type from Talamanca, Costa Rica. No. ^il-fy U. S. National 

 Museum. Collected by Wm. Gabb. 



Distribution. — Humid tropical forests of eastern Costa Rica. 



Characters. — Entire upperparts black with underlying dark yel- 

 lowish or ferruginous brown shining through ; underparts rich deep 

 ferruginous ; pelage thin ; hair on back coarse, stiff, and glossy ; under 

 fur short and thin ; tail long and narrow. 



Color. — Upperparts, including crown, base of tail, sides of neck, 

 and outside of legs, nearly uniform glossy black with yellowish or 

 ferruginous brown of underlying color shining through ; top of nose, 

 chin, and sides of head dingy grayish brown ; ears blackish with thin 

 tufts of black hairs at tips and conspicuous basal patches of ferrugin- 

 ous; feet varying from black to grizzled ferruginous brown, latter 

 color sometimes extending as a wash over outside of legs ; entire un- 

 derparts rich ferruginous, sometimes varied with irregular white areas ; 

 tail above black, thinly washed with white ; below with median area 

 black grizzled with ferruginous or yellowish brown, narrowly bordered 

 with black and thinly edged with white. Hairs on back shining black 

 with broad median ring of rusty buffy or rufous brown. 



Variation. — The underlying color of the back and the ear patches 

 vary from yellowish brown to rich ferruginous. The darkest, most 

 intensely colored specimen is from Santa Clara and has the median 

 rings on hairs of back nearly as deep ferruginous as the underparts. 



Measurei}ients. — Average of four adults from eastern Costa Rica 

 (from dry skins): total length 517.5; tail vertebrse 246.5; hind 

 foot 62.2. 



Cranial characters. — Premolars \. Skull (pi. II, fig. 6) even 

 broader and stouter than that of S. boothice belti ; rostrum much 

 broader and heavier; interorbital breadth much greater; occiput 

 broader. The type skull measures : basal length 50 ; palatal length 

 26.2; interorbital breadth 22; zygomatic breadth 35.5; length of 

 upper molar series 1 1.5. 



General notes. — This species seems to occupy the more humid 

 area of eastern Costa Rica, ranging inland to the border of the more 

 arid western slope where it meets 6^. adolphei dorsalis. It may be 



