Simia jacchus, Linn., Syst. Nat., i., p. 40 (1766).
Jacchus pencillatus, Geoffr. Ann. Mus., xix., p. 119 (1812); Spix, t. c. p. 34, pl. 26 (1823).
Jacchus leucocephalus, Geoffr., t. c. p. 119.
Jacchus vulgaris, Geoffr., t. c. p. 119; Gray, Cat. Monkeys Brit. Mus., p. 63 (1870, in part).
Hapale jacchus, Kuhl, Beitr., Zool., p. 46 (1820); Schleg., Mus. Pays Bas, vii., p. 271 (1876).
Hapale albicollis, Spix, Sim. et Vespert. Bras., p. 33, pl. 25 (1823); Geoffr., Cat. Méth. Primates, p. 59 (1851).
Characters.—Head small; eyes gentle; nose flat; face black, with a white spot in front; ears naked, with a tuft of long hairs on the front edge of its opening, either black, white, or grey; hair of the sides of the head elongated; back cross-banded with black and grey, the hair at the base dusky, reddish-brown in the middle, grey at the top. Tail banded with black or grey.
Several species have been described under the names of the White-necked Marmoset (H. albicollis, Spix), the Black-eared Marmoset (H. penicillata, Kuhl), and the White-headed Marmoset (H. leucocephala, Kuhl), but Dr. Gray considered these to be only varieties of the common species, which has sometimes the head and neck greyish-white, or the head, neck and ear-tufts black, or the head alone white.
Distribution.—Island of Marajo, at the mouth of the Amazon.
Habits.—The Common Marmoset is an inhabitant of the forests, feeding chiefly on fruits and insects. It is very susceptible to cold, and lives but a short time when removed from the tropics, unless extreme care be taken. Mr. Bates, the author of "The Naturalist on the River Amazons," states that when in Para, he counted in a short time thirteen different species of Monkey in semi-domestication in the city, either at the doors or windows of houses, or in the native canoes. Two of them he did not meet with afterwards in any other part of the country. One of these was the well-known Hapale jacchus, a little creature resembling a Kitten, banded with black and grey all over the body and tail, and having a fringe of long white hairs surrounding the ears. It was seated on the shoulder of a young mulatto girl as she was walking about the street, and he was told that it had been captured in the island of Marajo.