HABITS.--The Hairy Saki is a very timid and inoffensive animal, and is also, as Mr. Bates tells us in his well-known book, "very delicate, rarely living many weeks in captivity; but anyone who succeeds in keeping it alive for a month or two, gains by it a most affectionate pet. One of the specimens now in the British Museum was, when living, the property of a neighbour of mine at Ega. It became so tame in the course of a few weeks that it followed him about the streets like a dog. My friend was a tailor, and the little pet used to spend the greater part of the day seated on his shoulder whilst he was at work on his board. It showed, nevertheless, great dislike to strangers, and was not on good terms with any other member of my friend's household than himself.... The eager and passionate _Cebi_ seem to take the lead of all the South American Monkeys in intelligence and docility, and the Coaita, one of the Spider-Monkeys (_Ateles paniscus_), has, perhaps, the most gentle and impressionable disposition; but the Parauacú, although a dull, cheerless animal, excels all in this quality of capability of attachment to individuals of our own species, nor is it wanting in intelligence." {185}II. THE WHITE-HEADED SAKI. PITHECIA PITHECIA. _Simia pithecia_, Linn., Syst. Nat., i., p. 40 (1766). _Simia leucocephala_, Audeb. Singes., Fam, vi., Sect, i., p. 9, fig. 2 (1797). _Pithecia adusta_, Illig., Abh. Berl. Ak., 1804-1811, p. 107; Kuhl, Beitr. Zool., p. 44 (1820). _Pithecia nocturna_, Illig., l. c.; Schl., Mus. Pays Bas, vii., p. 217 (1876; part). _Pithecia leucocephala_, Geoffr., Ann. du Mus., xix., p. 117 (1812); Gray, Voy. Sulphur, Zool., p. 12, pl. 2; id., Cat. Monkeys Brit. Mus., p. 59 (1870; part); Scl., P. Z. S., 1871, p. 228. _Pithecia ochrocephala_, Kuhl, Beitr. Zool., p. 44 (1820, = young). _Pithecia rufibarbata_, Kuhl, t. c. p. 44 (1820). _Pithecia capillamentosa_, Spix, Sim. et Vespert. Bras., p. 16, pl. 11 (1823). _Pithecia rufiventer_, Geoffr., Cat. Méth. Primates, p. 55 (1851); Gray, Cat. Monkeys Brit. Mus., p. 60 (part, 1870); Wagner, Abhandl. Akad. Münch., v., pt. 2, p 436 (1848: = [female]). _Pithecia chrysocephala_, Geoffr., Cat. Méth. Primates, p. 55 (1851). _Pithecia pogonias_, Gray, Voy. Sulphur, p. 13, pl. 2 (1844). CHARACTERS.--MALE.--Hair black, very long over the body, and especially on the tail. Head with short hair, white, washed with yellow and divided by a central nude black streak; the white hair becoming yellow on the cheeks. FEMALE.--Greyish-black, washed with pale yellow, the hairs being tipped with the latter colour; moustache yellow; belly red. YOUNG MALE.--Belly rufous brown. {186}DISTRIBUTION.--Interior of Demerara, Kaicteur Falls; Rio Negro, and Rio Branco in Amazonia; Cayenne; Surinam. III. THE BLACK SAKI. PITHECIA SATANAS. _Saki noir_, F. Cuv., Hist. Nat. Mammif., pl. 78.