QUADRUMANA. 71 
Nocruorus, Fred. Cuv.—Nycririruecus, Spix. Improperly 
called Aotus by Mlliger. 
Only differs from the Sagouins in its great nocturnal eyes, andvin 
the ears, which are partly hidden under the hair. One species only 
is known. 
Nocth. trivirgata, Fred. Cuv., Mammif.; Nyctipith. vociferans, 
Spix, pl. 18. (The Douroucouli.) Ash-coloured above, yel- 
lowish beneath; a black vertical line on the middle of the fore- 
head, and one on each temple. It is a nocturnal animal of 
South America.(1) 
They are all from Guiana or Brazil. 
OuistTitis.—HaPpa.e, Illig—Arcroriruscus, Geoff. 
A small genus, similar to the Sakis, and for a long time confounded 
with them in the great genus of monkeys. In fact, like the genera- 
lity of the American monkeys, they have the head round; visage 
flats nostrils lateral; buttocks hairy; no cheek-pouches, and, like the 
Sakis in particular, the tail not prehensile. They have only, how- 
ever, twenty grinders, like the monkeys of the eastern continent; all 
their nails are compressed and pointed, those of the hind thumbs 
excepted, while their anterior ones are so slightly separated from 
the fingers, that it is with hesitation we assign to them the name of 
quadrumana. They are pretty little creatures, of agreeable forms, 
and easily tamed. 
M. Geoffroy distinguishes the Ouistitis, properly so called, which 
he names Jaccuus, and whose peculiar characters are pointed in- 
ferior incisors, arranged on acurved line, equal to the canines. Their 
tail is annulated and well covered with hairs; the ears generally or- 
namented with a tuft. 4 
Sim. jacchus, Lin.; in Paraguay the Ziti. (The Common. 
Ouistiti.) Tail tolerably well tufted, coloured in rings of 
brown and white; body greyish-brown; two large tufts of white 
hairs before the ears. From nearly every part of South Ameri- 
ca.(2) , 
N.B. This name of Gigo or Guigo is given by Pr. Max. to his Melanochir, 50 that 
we must consider it generic. 
(1) Add Wyctipithec. felinus, Spix, pl. 18. . 
(2) It is difficult to establish very specific limits between Ouistitis of different 
colours. The Jucch. penicillatus, Geoff., Spix, pl. 26, has a white spot on the 
forehead, and the tufts of the ears brown or black.—His J. lewcocephalus, Pr. Max., 
lib. 2, has the same tufts, but the whole head and fore part of the neck are 
_ white.—His J. humeralifer has the breast, shoulders and. arms white.—The J. al- 
\ bicollis, Spix, pl. 25, has the spot on the forehead, tufts of the ears and a large 
. 
