Alouatta discolor of Spi'x. 423 



Mycetes discolor*. The skins are so strikingly different in 

 colour from those of A. belzebul that it is at once evident that 

 discolor must be recognized as specifically distinct from 

 belzebul. The series includes an adult male individual 

 which is quite in agreement with Spix's description and 

 plate. 



The following is a brief account of the general appearance 

 of this monkey : — 



Size of body, in adult male, a little smaller than in 

 A. belzebul. 



Top of head and shoulders brownish black, many of the 

 hairs with reddish-orange tips. Forehead and whiskers 

 black. Back, from shoulders to rump, golden brown, a 

 broad, dark, indistinct stripe extending down the mid line, 

 the golden-brown colour being most evident on the flanks. 

 Rump and upper sides of hind limbs black. Inner sides of 

 thighs reddish brown. Upper sides of fore limbs black. 

 Backs of hands and feet black speckled with red. Fingers 

 and toes clothed with long yellowish-red hair. Under surface 

 of body nearly naked, a few golden hairs on the belly and 

 under sides of hind limbs. Throat with dense black beard. 

 Basal half of tail black, speckled with reddish orange, the 

 orange colour becoming more dominant towards the apical 

 portion ; tip yellowish orange. 



In another male individual the colour-scheme is much the 

 same, but the black regions are brownish, giving the animal 

 a much lighter appearance. 



The above description is sufficient to show how markedly 

 different this species is from A. belzebul, and though both 

 species appear to exhibit a considerable degree of colour- 

 variation, there can be no question as to the specific differences 

 between the two forms. 



In A. discolor the females are very unlike the males, being 

 both smaller in size and very different in colour. The 

 females of A. belzebul are. also smaller than the males, though 

 not to such a marked extent as in discolor. As regards the 

 colour, in A. discolor the females appear very much lighter 

 than the males. In one individual the general colour of the 

 upper surface is pale yellowish brown, slightly darker down 

 the mid line. Limbs olive-black above, speckled with yellow. 

 Backs of hands pale yellowish grey. B tcks of feet reddish 

 orange ; the toes clothed with long yellow-coloured hairs. 



The females would appear to be quite as variable in colour 



* Spix, Sim. et Vesp. Bras. 1823, p. 48, pi. xxxiv. 



