_Stentor niger_ (male), _S. stramineus_ (female), Geoffr., Ann. Mus., xix., p. 108 (1812; nec Spix). _Mycetes caraya_, Less., Sp. Mamm. Bimanes et Quadrum., p. 122 (1840); Gray, Cat. Monkeys Brit. Mus., p. 41 (part). {196}_Aluatta nigra_, Slack, Proc. Acad. Nat. Sci. Philad., 1862, p. 518. _Mycetes niger_, Thomas, P. Z. S., 1880, p. 394; Schl., Mus. Pays Bas, vii., p. 149 (1876). CHARACTERS.--MALE.--Hair rather long and entirely of a deep black; hair on the back of the head directed forward, meeting at right angles that of the forehead, which is directed backward, forming a well-marked semi-circular ridge. Length, 20 inches; tail, 17 inches. FEMALE AND YOUNG.--Pale straw-colour washed with black; the tips of the frontal ridge of hair black; at birth the young are entirely straw-colour. Dr. Slack observes that, in the young, about the period of the second dentition, the hairs upon the mid-line of the back become black at their bases; soon after, the change takes place upon other parts of the body, the black gradually taking the place of the straw-colour, until the entire body in the adult male is of an intense black colour--the adult female having the coloration of the half-grown male. Mr. Oldfield Thomas, who examined a specimen collected by Mr. Buckley, in Ecuador, points out that it agreed exactly with Humboldt's original description of the female of his _Simia caraya_, which he describes as having a black head and back, while the sides and belly are yellow. In all recent descriptions, however, the male is described as being nearly uniformly black, and the female uniformly yellow; so that Mr. Buckley's specimen appears to be just such an intermediate specimen as Humboldt described. According to Prof. Schlegel, adult males sometimes have the black on the hands and feet mixed with yellow. {197}DISTRIBUTION.--This is the species of Howler which ranges furthest to the south. It occurs most abundantly in Southern Brazil, Paraguay, and Bolivia, but Mr. Bates records his having obtained a specimen at Villa Nova, on the Upper Amazons, which had come from above Borba, on the Rio Madeira. He did not, however, meet with it on any other part of the Amazon region. Mr. Graham Kerr saw it in troops on the banks of the Pilcomayo river. HABITS.--Like nearly all the Howlers, the present species is of a sulky disposition, in captivity slinking away out of sight when approached. The members of this genus are the only Monkeys which the Indians have not succeeded in taming. They rarely survive their captivity many weeks. III. THE YELLOW-HANDED HOWLER. ALOUATTA BEELZEBUL. _Simia beelzebul_, Linn., Syst. Nat., i., p. 37 (1766). _Mycetes rufimanus_, Kuhl, Beitr. Zool., p. 31 (1820). _Mycetes discolor_, Spix, Sim. et Vespert., Bras., p. 48, pi. xxxiv. (1823). _? Colobus chrysurus_, Gray, Ann. Nat. Hist., xvii., p. 77 (1866).