42 
MAMMALIA. 
Aotus trivirgatus .— The Douroucouli. 
Plate IV. fig. 10. 
Hair of the body gray, mixed with white, exhibiting a silvery 
lustre in the sun, and a brown line passing down the back; fore¬ 
head with three black divergent lines; face blackish and hairy ; 
mouth surrounded by bristly hairs ; palms of the hands white ; 
tail brushy, half as long again as the body; no external ears. 
Length of the body nine inches and a half. Inhabits the forests 
of Maypura and Esmeralda, South. America. 
Genus 14.— Pithecia. — Desmarest. 
Generic Character .—Incisors canines j-J, grinders > to¬ 
tal 36. Facial angle 60 degrees ; ears rounded; tail a little 
longer than the body, not prehensile, and covered with long 
hair; feet with five toes; nails short and sharp. 
Pithecia rufiventer _ The Fox-Tailed Monkey. 
Plate VI. fig. 3. 
Fur dusky brown, with a slight rusty tinge, except on the 
head and face; from the top of the nose to the chin it is black; 
face dark brown, surrounded by white downy hair, which rises 
on each side of the forehead, like a wig, diverging from the cen¬ 
tre of the forehead; bushy at the cheeks; eyes large; ears 
round and flat; tail equal to the length of the body, thick, like 
that of a fox, but more bushy. Size of a domestic cat. In¬ 
habits French Guiana. 
Genus 15.— Jacchus. — Desmarest ♦ 
Generic Character. —Incisory teeth \ t canines J-J, grinders 
; total 36. Facial angle 50 degrees; head round; muzzle 
short; occiput prominent; tail longer than the body, soft, and 
entirely covered with hair; feet with five toes ; the thumbs of 
the anterior hands in the same direction as the fingers, and not 
opposable; nails very long, compressed, arched, and pointed. 
Sub-Genus I.— Ouistiti.— Geoffroy .—Intermediate incisory 
