164 ALLEN’S NATURALISTS LIBRARY. 
Distribution—Upper Amazon. Of all the species of the 
genus, this ranges furthest to the south—to 14° S. lat. 
VIII. THE BLACK-FRONTED TITI. CALLITHRIX NIGRIFRONS. 
Callithrix nigrifrons, Spix, Sim. et Vespert. Bras., p. 21, pl. 15 
(1823); Gray, Cat. Monkeys Brit. Mus., p. 56 (1870) ; 
Schl., Mus. Pays Bas, vil., p. 232 (1876). 
Characters.—Nearly allied to the Masked Titi (C. Aersonata), 
but distinguished by the nearly white back of the head and 
nape of the neck, and by the hairs at the base of the tail 
being entirely red. 
Distribution Upper Amazonia. 
IX. THE RED-BELLIED TITI. CALLITHRIX CASTANEIVENTRIS. 
Callithrix castaneoventris, Gray, Ann. and Mag. N.H., xvil., p. 
58 (1866) ; id., Cat. Monkeys Brit. Mus., p. 56 (1870). 
Callithrix caligata, Wagner, Arch. f. Naturg., 1842, 1, p. 454 
(ex Natterer, MSS.); Schl., Mus. Pays Bas, vii., p. 237 
(1876). 
Characters—Fur of the same nature as in C. cufrea, black, 
ringed with grey ; face grizzled, whiskers, throat, chest, under 
side of the body, and inner surface of the limbs reddish-chest- 
nut ; outside of the limbs grizzled, washed with rufous ; fore- 
head, hands, feet and tail black ; tip of the tail paler. 
Distribution Paraguay and Brazil ; Borba, Rio Madeira. 
The two following species may be distinguished from those 
already described by having their soft woolly fur entirely free 
from the long bristly hairs, which were dispersed through the 
fur of the otbers. 
