_Pithecia_, Geoffr., Ann. Mus., xix., p. 115 (1812).
_Chiropotes_, Gray, Cat. Monkeys Brit. Mus., p. 60 (1870), in part.
The Sakis form the second section of the present Sub-family, and are
characterised by their long, thick, and bushy non-prehensile tail. A thick
beard conceals the large chin. Hair on the crown long, divided by a central
line, and hanging over the head, half concealing the pleasing diminutive
face, or confined to the head, cheeks, and chin. The ears are large. The
upper and lower incisor teeth project forward, the upper inner pair being
moderately large, the outer very small; canines strong and conical; first
pre-molar smaller than the others, and one-cusped; molars with square
crowns, grooved in the middle and slightly four-cusped.
In the brain the whole of the cerebellum and the olfactory lobes are
covered by the cerebrum. In general form the latter resembles that of the
species of _Cebus_. The frontal and occipital regions of the skull
approximate in form to those in Man; the angle of the mandible is expanded,
but less so than among the Howlers (_Mycetes_). The ribs are relatively
broader in this genus than in any other of the American Monkeys.