QUADRUMANA. : 67 
ascend very high for the purpose of lodging a bony drum, formed 
by a vesicular inflation of the hyoid bone, which communicates with 
the larynx, and gives to their voice astonishing power, and a most 
frightful sound. Hence their name of Howling Monkeys. The pre- 
hensile portion of the tail is naked beneath. ’ 
There are several species, whose distinguishing characters are 
not yet well ascertained, for the colour of the fur on which they are 
established varies with the age and sex. : 
Simia seniculus, Buff. Supp. VII, 25. (Red Howling Mon- — 
key.) It is often sent to us from the forests of Guiana, 
where it lives in troops; size that of a large fox ; colour, a red-_ 
dish chesnut, rather deeper at the head and tail. The llouatte 
ourson (Stentor ursinus, Geoff.), Humb. Obs. Zool. I. pl. 50, * 
must differ from it, although slightly ; but it would appear that’ 
there are many others, some of which are brown or black, others 
ofa pale colour. In certain species this pale tint is peculiar to 
the females.(1) - 
The Common Sarasous have the head flat, and the projection of the 
muzzle very moderate—facial angle 60°. 
In some of them, the anterior thumbs are either totally, or nearly — 
so, hidden under the skin, and the prehensile part of the tail naked, 
beneath. M. Geoff. has formed them into a genus by the name of 
ATELEs.(2) 
The first species, the Chamek, Ateles pentadactylus, Geoff. 
ey 
X 
(1) Marcgrave, Braz. 226, speaks of a black Guariba, with brown hana that © 
Spix thought he had found in his Seniculus niger. Mem. de Munic, for 1813, p. og 
333. Mycetes rufimanus, Kuhl. th 
Marcgrave, 227, speaks of another species, all black and bearded, fig. p. oe 
under the wrong name of Exquima, which must have been, it is probable, the 
Mycetes barbatus, Spix, pl. 32. The female, ib. pl. 33, is of a light yellowish 
grey. The male must be the Mycetes niger of Kuhl and Prince Maximil. de Neu- 
wied. The Caraia of d’Azzara, which is black; breast and belly ofa dark red ; 
the female brownish ; may be referred to this species. i * 
Pr. Max. has another Mycetes ursinus, which appears to be much browner than 
the ursinus of M. Geoffroy, and to approximate nearer to the M. fuscus, or the M. 
discolor of Spix, pl. 30 and 34. This latter rather appears to be the St. fuscus of 
Geofiroy. 
» The Straw-coloured Alouatte, Stentor Pee Geoff. andthe Myc. stramineus, 
_- Spix, pl. 31, of a yellowish grey, appears from its cranium to be of a different 
‘species, but it may merely be the female of a preceding one. It is easily seen, 
also, that if their characters are so sith a their synonymes must be much 
_ more so. 
; L Add the St. flavicaudatus, Geoff. of a black brown, with a yellow streak on each 
side of the tail. 
' (2) Ann, du Museum, Vu, 260, et seq. 
