THE ANNALS 



▲NO 



MAGAZINE OF NATURAL HISTORY, 



No. 105. OCTOBER 1845. 



XXII. — On the Howling Monkeys (Mycetes_, Illiger). 

 By J. E. Gray, Esq., F.R.S. &c. 



Much attention has been paid by various zoologists to tlie spe- 

 cies of Monkeys of the Old World, but as yet little consideration 

 has been devoted to those of the western hemisphere, and pro- 

 bably zoologists have been deterred from attending to them on 

 account of the difficulty of the subject. 



Humboldt in his 'Zoological Observations,^ Prince Maximilian 

 and Spix in their works on Brazilian zoology, are almost the 

 only modern authors who appear to have written on them from 

 the personal examination of the specimens, having moreover en- 

 joyed the advantage of observing them in their native forests. 



Spix described one of the species, M. Caraya, as being black 

 in the male and yellow in the female and young ; and Prince 

 Maximilian observes that the males and the specimens of M. ur- 

 sinus from the more northern regions of Brazil are rufous or fer- 

 ruginous, whilst the female and those from the more southern 

 regions are brown or blackish brown, and Lichtenstein describes 

 the young of this species as blackish. Cuvier observes, that there 

 is very little difference between M. ursinus and M. seniculus. 



We have been fortunate at the British Museum in having pro- 

 cured a considerable number of specimens of this genus, and 

 as I find amongst those that have been received at the same time 

 or from the same localities the two sexes of nearly the same colour, 

 and the young and adult equally so, I am inclined for the pre- 

 sent to regard them as species ; at the same time I must confess 

 that some of the specimens of the same apparent species vary 

 considerably in tint, and that some of the black species have so 

 many red hairs scattered amongst their fur when it is bent back 

 and examined, as to make one almost doubt if the black are not 

 another state or local variety of the red ones. 



Under these difficulties, I think it is desirable that the various 

 Ann. ^ Mag. N, Hist, Vol.xwl R 



