1880.] MR. \Y. A. FORBES ON THE UAKARI MONKEYS. G4o 



sentative form of P. chiropotes, I am unable to agree with Dr. 

 Gray {I. c.) as to Spix "having evidently described the teeth &c. of 

 his first species iu his generic character," for I find the characters 

 there given apply equally well to both the forms under consideration. 

 Indeed, as the "character essentialis " of the genus Brachyurus is 

 " Cauda non volubili, abbreviata,'' B. israelita, in which that organ 

 is of the normal length, cau in no way be considered the tvpe of 

 the genus. "With certain other points, too, of the " descriptio '" there 

 given, B. oualianj corresponds better than the first species. I 

 therefore agree with Isidore Geoffroy (Exped. Am. Sud, Mammif. 

 p. 18) in retaining the generic name Brachyurus, of which Oualaria 

 thus becomes a synonym^ 



As regards the species of this genus, there are three well-marked 

 ones, each inhabiting a distinct geographical area ; of each of 

 these I have seen skins and skulls. They may be arranged as 

 follows : — 



a. Facie nigra. 



1. Brachyurus melanocephalus. (Plate LXIII.) 



Simia tnelanocephala (Cacajao), Humboldt, Rec. pi. xsix. p. 317 

 (1811). . 



Pithecia melunocephala, Geoffr. Ann. Mus. xix. p. 1 1 7 (1812). 

 Brachyurus ouakary, Spix, Sim. et Vesp. Bras. p. 12, pi. viii. 



(182;3). 



Oualcaria spixii, Gray, P. Z. S. 1849, p. 10, fig. 



Oualaria melanocephala, Gray, Cat. Monkeys &c. p. 62 (1870). 



Pithecia melanocephala, Schlegel, Mus. P.-B. vii. p. 227 (187G). 



Ater, dorso lateribusque cum brachiis ^wsticis 2'tvs minusve 

 castaneo-brtnmeis. 



Hab. Forests traversed by the Casiquiare and Rio Negro 

 (Humboldt) ; forests between the Solimoes and lea {Spix) ; Mara- 

 bitanas, Rio Negro, and Moura, Rio Branco (Natterer, fide Pelzeln 

 apud Schegel, I.e.). 



This species is at once distinguishable by its black face, as well 

 as by the black hands, feet, &c. "it is the most northern form of 

 the three, and ajjparently the most wide-spreading also. No doubt 

 it is the " black-faced, grey-haired " species heard of, but not 

 obtained, by Mr. Bales as being found " 180 miles from the mouth 

 of the Japuni" (Nat. Amaz. ii. p. 313). 



Of this species we have, at different times, had two specimens 

 living iu the Gardens {vide Sclater, P. Z. S. 1870, p. 1). From 



1 The name Erachi/unis lias also been used, but erroneously (cf. Sclater, 

 ' Ibis,' 1877, p. 200), for the Ant-Thrushes {Pitta). Mr. Alston has, smce this 

 paper was read, pointed out to me that the same term also had been proposed 

 some years previously to Spix by Fischer (' Zoognosia,' i. p. 24) for a genus of 

 Eodeutia (1813). As, however, this name has never, I believe, been adopted 

 for use in that group, it seems to me quite unnecessarv. on that gi-ound, to 

 reject the name for the Uakaris. Purists will have, I suppose, to adopt Lesson's 

 barbarous term, proposed as a subgenus, Cacaiuo (Species des MammifHres, 

 p. 181 , 1840). 



