58 MAMMALIA. 



Both of them of different browns; in the first, the circumference of the face 

 is blackish; in the second it is whitish; but the shade of colour in all the 

 rest of their bodies varies between a brownish black and a fawn-colour, 

 sometimes even a white. The shoulders and breast are however generally 

 lighter and the calotte and hands darker. 



Others, again, have the hairs of the forehead so disposed as to form a 

 kind of aigrette, such as the 



Sim. fatuellus, Gm. (The Horned Sajou.) This animal has a tuft of 

 black hairs on each side of the forehead. 



The disposition of these Monkeys is mild and gentle, their motions^quick 

 and light, and they are easily tamed. Their name of Weeping Monkeys is 

 derived from their soft plaintive voice. 



In the Saimiki the tail is depressed, and almost ceases to be prehensile; 

 the head is very much flattened; in the interorbitar partition of the skeleton 

 there is a membranous space. There is only one known; the 



Simla sciurea, Buff. (The Siamiri.) Size of a Squirrel; of a yellowish 

 grey; fore-arms, legs, and the four extremities of a yellowish fawn-colour; 

 end of the nose black. 



Those of the American monkeys, whose tails are not at all prehensile, are 

 called Sakis. Several of them have that appendage long and tufted, whence 

 they have been also termed Fox-tailed Monkeys: their teeth project for- 

 wards more than those of the others. They are the Pithecia of Desmarets 

 and lUiger. 



Simla pitheclaflj. (TheYarke.) Blackish; circumference of the face 

 whitish. 



Spix distinguishes those species whose tails, although tufted, are shorter 

 than the body, by the name of BBACHitriitrs. His £r. Ouaraki has a fawn- 

 coloured body; head, neck, arms and feet black. 



In some, also, the Callithrix, Geoff, or Sagouins, Fr. Cuv. the tail is 

 slender, and the teeth do not project. The Saimiri were associated with 

 them for a long time, but the head of the Sagouins is higher, and their 

 canine teeth much shorter. Such is the 



Call. perso7iata, Geoff. (The Masked Monkey.) A yellowish grey; head 

 and hands black. The 



NocTHOHus, Fred. Cuv. 

 Only differs from the Sagouins in its great nocturnal eyes, and in the 

 ears, which are partly hidden under the hair. One species only is known, 

 Nocth. irivlrgata, Fred. Cuv. (The Douroucouli.) Ash-coloured above, 

 \^ yellowish beneath; a black vertical line on the middle of the forehead, and 

 one on each temple. It is a nocturnal animal of South America. 

 They are all from Guiana or Brazil. 



OUISTITIS. 



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 generality of the 



