206 ALLEN’S NATURALISTS LIBRARY. 
ever, are not yet numerous enough, nor exact enough, to enable 
those who have only studied the species alive in Europe, or had 
skins, to decide with such imperfect data as to their sex, age, 
and habitat. Not until some naturalist has made’a prolonged 
study of these animals in their native country, and watched 
their conduct and relations in the living state, can we hope to 
attain to any certain knowledge of how many species the genus 
contains ; and of the differences between the old and young of 
both sexes at different periods from youth to age. 
I, VRE WHITE-THROATED CAPUCHIN... CEBUS. HYPOLEUCUS. 
Sat & gorge blanche, Buffon, Hist. Nat. Mamm., p. 64, pl. 15, 
fig.9 (1767); Fr.Cuv., Hist. Nat. Mamm., livr.xvi.; Audeb., 
Hist. Nat. Singes, fam. v., sect. 2, pl. 5 (1797). 
Simia hypoleuca, Humb., Obs. Zool., i., p. 337 (1811); Pucher., 
Rev. et Mag. de Zool. (2), 1857, p. 348. 
Cebus hypoleucus, Geoffr., Ann. Mus., xix., p. 111 (1812) ; Gray, 
Cat. Monkeys Brit. Mus., p. 50 (1870); Schl., Mus. Pays 
Bas, vii., p. 190 (1876). 
Cebus leucocephalus, Gray, P. Z. S., 1865, p. 827, fig. 4; Sclater, 
P. Z. S., 1872, p. 4; Alston in Godman and Salvin, Biol. 
Centr. Am. Mamm., p. 13 (1879). 
Characters.—Hair very silky, smooth and stiff, and thicker 
above than below. Face and forehead nude, flesh-coloured; 
hands and feet nude, of a violet hue, as also the thinly- 
haired skin of the under side of the body. The tip of the tail 
fora short distance being naked, distinguishes this species from 
all others. Shoulders, arms, and sides of the head behind the 
ears pure white ; chest and throat yellowish ; rest of the body 
deep black. 
