_Hapale weddelii_, Schl., t. c. p. 262. CHARACTERS.--Fur of back ringed with grey; that of the head, neck, and front of the fore- and hind-limbs, tail, hands, and feet black; loins, thighs, legs, and base of tail bright maroon. DISTRIBUTION.--Obtained by MM. Castelnau and Deville, at Sarayacu, in the Peruvian Amazons. VII. THE BLACK-FRONTED TAMARIN. MIDAS NIGRIFRONS. _Midas nigrifrons_, Geoffr., Cat. Méth. Primates, p. 64 (1851). _Midas flavifrons_, var. c. _Midas nigrifrons_, Gray, Cat. Monkeys Brit. Mus., p. 67 (1870). _Hapale nigrifrons_, Schl., Mus. Pays Bas, vii., p. 263 (1876). {144}CHARACTERS.--Differs from _M. weddelli_ in having the fur washed with rufous, and the hairs finely ringed. DISTRIBUTION.--Unknown. VIII. THE BROWN-HEADED TAMARIN. MIDAS FUSCICOLLIS. _Midas fuscicollis_, Spix, Sim. et Vespert. Bras., p. 27, pl. 20 (1823). _Midas flavifrons_, Is. Geoffr., Cat. Méth. Primates, p. 64 (1851); Castelnau, Expéd. Amér. Sud, Mamm., pl. vi., fig. 1 (1855); Gray, Cat. Monkeys, Brit. Mus., p. 67 (1870). _Midas devillii_ (nec Is. Geoffr.), Slack, Proc. Acad. Nat. Sc. Philad., 1861, p. 464. _Hapale fuscicollis_, Schl., Mus. Pays Bas, vii., p. 264 (1876). _Hapale chrysomelas_ (nec Kuhl), Schl., t. c. p. 254. CHARACTERS.--Pelage mostly black; head and face brown or reddish-brown, with some grey hairs; lips white, but the nose black; top of the head yellow, or yellowish-red; back yellow and black; hands and feet black; outside of the limbs and base of the tail reddish; under side of the body and inside of the limbs brownish-red. The female differs in having the outside of the limbs and the underpart of the body blackish. DISTRIBUTION.--Brazil. HABITS.--Nothing is known of the individual habits of this species. IX. THE YELLOW-TAILED TAMARIN. MIDAS CHRYSOPYGUS. _Hapale chrysopyga_, Wagner, in Schreb. Säugeth., i., Simiæ, p. 249 (1840); Schl., Mus. Pays Bas, vii., p. 254 (1876). CHARACTERS.--Similar to _M. fuscicollis_. Black, with the thighs, legs, and base of tail rusty-red. DISTRIBUTION.--Brazil, near Ypanéma, Province of St. Paulo. {145}X. THE BLACK AND RED TAMARIN. MIDAS NIGRICOLLIS. _Midas nigricollis_, Spix, Sim. et Vespert. Bras., p. 28, pl. 21 (1823). _Midas rufoniger_, I. Geoffr. et Deville, C. R., xxvii., p. 499 (1848); Is. Geoffr., Cat. Méth. Primates, p. 64 (1851); Castelnau, Expéd. Amér. Sud, pl. v., fig. 3 (1855); Gray, Cat. Monkeys Brit. Mus., p. 67 (1870). _Hapale nigricollis_, Schl., Mus. Pays Bas, vii., p. 264 (1876). CHARACTERS.--Differs from _M. fuscicollis_ in having the back, loins, thighs, and legs bright reddish-chestnut. (_Gray._) Mouth bordered with longish white hairs.