QUADRUMANA. 69 
Some of them have the hairs on the forehead of a uniform length, 
such as the 
Sim. appella, L. (The Sajou); atid the S. capucina, L.; Buff. 
XV,4, 5 and 8, 9. (The Capuchin.) Both of them of dif- 
ferent browns; in the first, the circumference of the face is 
blackish; in the second it is whitish; but the shade of co- 
lour in all the rest of their bodies varies between a brownish 
black and a fawn-colour, sometimes even a white. The should- 
ers and breast are however generally lighter, and the calotte 
and hands darker.(1) 
Others, again, have the hairs of the forehead so disposed as to 
form a kind of aigrette, such as the 
Sim. fatuellus, Gm.; Buff. Supp. VII, 29. (The Horned 
Sajou.) This animal has a tuft of black hairs on each side of 
the forehead.(2) 
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 Sarmrat the tail is depressed, and almost ceases to be pre- 
hensile; the head is very much flattened; in the interorbitar parti- 
tion of the skeleton there is a membranous space. There is only 
one known; the 
Simia sciurea, Buff. XV, 10. (The Siamiri.) Size ofa Squir- 
(1) The Sajous and the Sais vary so much from a brown to a yellow, that were 
there not intermediate varieties, we should be tempted to make many species of 
them. Such is the case with the Sim. trepida, syrichta, lugubris, flavia, L. and 
Schreb., as well as some of those distinguished by M. Geoffroy, Ann. du Mus. 
XIX, 111and 112. Spix has recently, and in our opinion improperly, multiplied 
them still more. 
We would refer to the Sajow (Sim. apella, Lin.) the Cebus robustus, Pr. Max., 
which appears to us an old one of that species. The Ceb. macrocephalus, Spix, pl. 
1, does not seem to differ from it, so far as regards the species. We refer to the 
Sai (S. capucina, Lin.) the Sat a gorge blanche, Buff. (S. hypolencos); the Cebus 
libidinosus, Spix, 2; the Ceb. xanthosternus, Pr. Max., or the Ceb. xanthocephalus, 
Spix, 3; the Ceb. cucullatus, id. 6. 
We should be more inclined to consider as distinet species, the Sajow 4 pieds 
dorés, Fred. Cuy., the Sajou brun, id. or Ceb. unicolor, Spix, pl. 4; the Sim. flavia, 
Schreber, 31, B, from which. the Ceb. gracilis, Spix, pl. 5, seems to differ only in 
the stuffing—but that we require numerous 4, Me made on the; spot which 
these animals inhabit, before we can hope to establish their species in any other 
_ than an arbitrary manner. 
(2) Here should come the Cebus cirrhifer, Geoff, and the Ceb. of the same name, 
of Pr. Max., but which is different. Ceb. cristatus, Fred, Cuy. 
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