SCIURIDAI—SCIURUS ASTUANS. ToT 
Sciurus gilvigularis NatTERER, MS.—WaGNER, Wiegm. Arch. f. Naturg. 1843, ii, 43, 1845, i, 148; Abband. 
d. K.-B. Akad. d. Wissensch. v, 1850, 279 (from near the mouth of the Rio Madeira, Brazil),— 
GIEBEL, Siiuget. 1855, 653 (from Wagner). 
Sciurus guerlingus CASTELNAU, MS. (= Macruxus leucogaster Gray ; see Gray, l. ¢.). 
Macroxus leucogaster GRAY, Ann. and Mag. Nat. Hist. 3d ser. xx, 1867, 430, 
Macroxus flaviventer CASTELNAU, MS.—Gray, Ann. and Mag. Nat. Hist. 3d ser. xx, 1867, 432. 
Macroxus kuhlii Gray, Ann. and Mag. Nat. Hist. 3d ser. xx, 1867, 433 (= Sciurus leucotis Castelnau, MS.) 
Myoxus guerlingus SHAW, Gen. Zool. ii, 1801, 171, pl. 156. 
Brazilian Squirrel, PENNANT, Quad. 1771, 286. 
Le Grand Guerlinguet, Burron, Hist. Nat. Suppl. vii, 1789, 261, pl. Ixv. 
Le Petit Guerlinguet, BurKON, Hist. Nat. Suppl. vii, 1789, 63, pl. xlvi. 
CGuerlinguet, Suaw, Gen. Zodl. ii, 1801, 171. 
Cachin gélé, Vulgo. 
Var, RUFONIGER. 
Sciurus rufoniger PUCMIERAN, Rev. de Zool. 1845, 336 (Santa Fé de Bogota). 
Sciurus chrysuros PUCHERAN, Rev. de Zool. 1845, 337 (Santa Fé de Bogota). 
Sciurus @estuans var. hoffmanni PETERS, Monatsb. Akad. Wissensch. Berlin, 1863 (1864), 654 (Costa Rica). 
Sciurus hyporrhodus Gray, Ann. and Mag. Nat. Hist. 3d ser. xx, 1867, 419. 
Macroxus irroratus GRAY, Ann. and Mag. Nat. Hist. 3d ser. xx, 1867, 431 (“ Upper Ucayali, Brazil’’). 
Macroxus griseogena Gray, Ann. and Mag. Nat. Hist. 3d ser. xx, 1867, 429 (Mexico, Honduras, Costa Rica, 
Panama, Santa Fé de Bogota); ib. 4th ser. xi, 1873, 469. 
Var. ZSTUANS. 
VaRIETAL cHARS.—Length of head and body 7.00 to 8.00 inches; of tail- 
vertebree a little less (about 6.75 to 7.50); to end of hairs about 9.00 to 9.50. 
Ears of medium size, rounded ; tail narrow, distichous till near the end, where 
it is more cylindrical. Pelage soft, short. General color above dark olivaceous- 
brown, minutely varied with fulvous or pale rufous; below, including inside 
of the limbs, generally reddish-yellow, varying from pale rufous to yellowish- 
gray. Sometimes with the yellow restricted to the breast and the middle of 
the anterior half of the lower surface; or the whole lower surface is whitish, 
washed with fulvous. Above, with the middle of the back, sometimes darker 
than the rest of the dorsal surface. Tail yellowish-brown, ringed with black 
(the subterminal black bar very broad), and washed with pale grayish-yellow. 
The general color of the tail is blackish, washed with pale whitish-yellow. 
The outer surface of the feet is usually colored like the back. The ears are 
generally reddish; the eye is ringed with brownish-yellow. The sides of 
the muzzle, the chin, and throat are yellowish-white. 
This variety presents no very striking variations in color, and seems to 
vary but little with locality. I have noticed no tendency to melanism, and no 
melanistic specimens appear to have been met with by previous authors. 
The subjoined table of measurements of fifteen specimens, nearly all (thirteen) 
taken from alcoholic examples, shows only a very moderate range of varia- 
tion. The specimens are nearly all from Southern Brazil, and are quite uni- 
