Mr. J. E. Gray on the Howling Monkeys. 219 
redder. It agrees well with the MW. stramineus, Spix, t.31. The 
young female is yellow-brown, darker on the shoulders; the 
adult is black slightly washed with yellow from the small yellow 
tips to the blackish hairs, and the other male is just intermediate 
in colour between the two females ; the latter nearly agrees with 
M. fuscus, Spix, t.30. In the Zoological Society’s museum are 
two females from British Guiana, which are of a uniform dark 
brown, with the hair between the shoulders very minutely yellow- 
tipped. 
2. The Golden Howler, Mycetes seniculus, Kuhl. Simia seniculus, 
linn. Royal Monkey, Penn.; Buffon, N. H. Supp. vii. t. 25. 
Reddish chestnut ; middle of the back golden yellow; hair 
one-coloured to the base, short, rather rigid, without any under- 
fur; of the head short. 
Inhab. Brazils. 
The Museum collection contains three adult males: we have 
no females of a different colour that would suit them, and we 
have none that have not their proper-coloured mates. 
3. The Silky Howler, Mycetes laniger. 
Reddish chestnut ; middle of the back golden yellow; hair 
elongate, very soft and silky, dark brown at the base, golden or 
chestnut at the tip, with a close under-fur; of the head rather 
elongate. 
Inhab. Columbia. Purchased at Paris. 
We have two males and two females of this species, an adult 
and half-grown specimen of each sex; one of the females has the 
end half of the tail decidedly rather paler, so that in this parti- 
cular it agrees with M. chrysurus of M. 1. Geoffroy ; but the other 
specimen varies a little in the intensity of the colour of this part, 
so that I cannot consider it of any importance. 
4. Black and Yellow Howler, Mycetes bicolor. 
Black ; hair rather rigid, uniform black, sides of the loins varied 
with yellow ; hair of this part black, with a broad subcentral red- 
dish-yellow band. 
Inhab. Brazils. 
We have an adult male; it is much hke M. Caraya im external 
appearance, but the hair of the forehead is decidedly reflexed, 
marking a distinct ridge. It is most like M. seniculus in texture 
of fur, &c., but very different-coloured. If it had not been of the 
same sex and age as our specimen of that species, I might have 
been inclined to have regarded it as identical. 
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