196 ALLEN’S NATURALISTS LIBRARY. 
Aluatta nigra, Slack, Proc. Acad. Nat. Sci. Philad., 1862, p. 
518. 
Mycetes niger, ‘Thomas, P. Z. S., 1880, p. 394; Schl., Mus 
Pays Bas, vil., 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 
Humbold: 3 original description of the female of his Szmza 
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 speci- 
men 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, 
ta eer 
