THE SPIDER-MONKEYS. 227 
based upon the development of the anterior thumbs, this mem- 
ber being absent in B. arachnoides, replaced by a small nail- 
less tubercle in 2. ¢uderifer, and surmounted by a nail in ZB. 
hemidactylus. In the “ Magazin” of Messrs. Verreaux, in Paris, 
I found specimens having upon one hand the tubercle, and upon 
the other the nailed thumb, others with the tubercle on one 
hand, but absent upon the other. St. Hilaire himself, in his 
“Catalogue of the Primates,” expresses a doubt as to whether 
B. arachnoides and B. hemidactylus are really distinct. In 
September and October, 1860, I was unable to find B. hemz- 
dactylus in the Paris Museum, all the Brachydeles being labelled 
Lriodes avrachnotdes.” 
Distribution Confined to the wooded region of the south- 
east of Brazil. 
Habits——Arboreal, diurnal, and (it is supposed) gregarious, 
frequenting the high forest trees, and subsisting on fruits. 
THE SPIDER-MONKEYS. GENUS ATELES. 
Ateles, Geoffr., Ann. Mus., vil., p. 262 (1806). 
_ This is the fourth remaining genus of the Ceézne, the last 
Sub-family of the Cedzd@. With the description of the Spider- 
Monkeys, therefore, we shall have passed in review all the 
species of the New World Platyrrhine section of the Anthro- 
foidea, ‘The species of this group derive their trivial name from 
their long and slender limbs ; the name applied to them, how 
ever, in their native forests by the Indians of Brazil is ‘‘Coaita.” 
They are characterised by their light and slender body, which 
is narrower across the loins than across the chest. The head 
is rounded, the forehead salient, and the muzzle somewhat pro- 
jecting. Both pairs of limbs are much elongated, the hind- 
Qz 
