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 {133}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. II. THE WHITE-SHOULDERED MARMOSET. HAPALE HUMERALIFER. _Hapale humeralifer_, Geoffr., Ann. Mus., xix., p. 120 (1812); Bates, Nat. Amaz., ii., p. 55 (1863). CHARACTERS.--Face partly naked, flesh-coloured; ears fringed with long white hairs. Fore-part of body white; hands grey; hind part black, with the rump and under side reddish-tawny; tail banded with grey and black; long white hair on the shoulders. Length about 8 inches, exclusive of the tail. DISTRIBUTION.--Mr. Bates says that this species seems to occur {134}only in the dry woods bordering the Campos in the interior of Brazil. HABITS.--"One would mistake it," writes Mr. Bates in reference to this rare little Marmoset--the prettiest species of its family--"at first sight for a Kitten, from its small size, varied colours, and the softness of its fur. It was a most timid creature, screaming and biting when anyone attempted to handle it. It became familiar, however, with the people of the house, a few days after it came into their possession. When hungry or uneasy, it uttered a weak querulous cry, a shrill note which was sometimes prolonged so as to resemble the stridulation of a grasshopper." III. THE WHITE-EARED MARMOSET. HAPALE AURITA. _Jacchus auritus_, Geoffr., Ann. Mus., xix., p. 19 (1812). _Hapale aurita_, Kuhl, Beitr. Zool., p. 48 (1820); Schl., Mus. Pays Bas, vii., p. 276 (1876).