Characters.—Black, slightly washed with yellow on the under side of the body and inner side of the limbs; hairs of the body soft, brown at the roots, black at the tips; hands and feet variable, reddish-yellow or reddish-brown, or grey, or black. Upper surface and tip of the tail, spot in front of the ears, and on the knees, reddish-yellow. Length of the body, 17½ inches; tail, 18½ inches.
This species differs from the Black Howler (A. nigra) by the brown colour of the roots of the hair; and from the species next to be described—the Brown Howler (A. ursina)—by the length of the fur and the absence of the reddish-brown tips to the hairs.
Distribution.—Apparently confined to the Lower Amazon, in the vicinity of Para.
Habits.—The same as those of the species already described.
IV. THE BROWN HOWLER. ALOUATTA URSINA.
Stentor ursina, Humb. and Bonpl., Obs. Zool., i., pl. 30 (fig. nec descr.; 1811).
Stentor flavicauda, Id. t. c. p. 355 (1811).
Stentor ursinus, Geoffr., Ann. Mus., xix., p. 108 (1812).
Stentor fuscus, Geoffr., t. c. p. 108 (1812).
Mycetes fuscus, Kuhl, Beitr. Zool., p. 29 (1820); Spix, Sim. et Vespert., Bras., p. 43, pl. 30 (1823).