51 S 



PROCEEDINGS OF THE ACADEMY OF 



Aluatta nigra. s 

 Stentor niger et straruinsea,* Geoff., Ann. du Mus. vol. xix., 1812, p. 108. 

 Simia caraya, Humb., Rec. de3 Obs. vol i, 1811, p. 394. 

 Mycetes barbatus, Spix, Sim. et Vesp. 1811, p. 45. 

 Icon, Spit, T. xxxiii. 



Hab. Brazil, Paraguay et Bolivia. 



A. Atra ; foemina et juniores straminei nigro varii. 



Adult. Male entirely of a deep-black color ; hairs of occiput directed forward, 

 meeting nt right angles those of the forehead, which are directed backward. 



Female and Young. Pale straw color dashed with black. 



The young of this species are at birth entirely of a pale straw color. About 

 the period of the second dentition the hairs upon the medio-dorsal line become 

 black at their bases ; soon after, this change takes place upon other parts of the 

 body, the black gradually taking the place of the straw color, until the entire 

 body iu the adult male is of an intense black color the adult female having 

 the coloration of the half grown male. Upon the forehead is a well marked 

 semicircular ridge of hairs formed by the meeting at nearly right angles of the 

 hairs of the forehead and occiput ; the tips of these hairs in the female are 

 black. 



Skulls Current No. 4619 (J 1 ; antro-posterior 5; occipito-frontal 3-2; bi- 

 temporal 2-2 ; bi-parietal 2 ; cranial capacity ? ; facial angle 40. Current No. 

 5136 9; antro-posterior 4-1 ; occipito-frontal 2-8 ; bi-temporal 2 ; bi-parietal 

 205 ; cranial capacity 4-25 ; facial angle 45. 



Lower Jaws. Current No. 4619 ; angle to symphysis 3-9; angle to condyle 

 31; angle to coronoid process 3; posterior molar to coronoid process 1-35. 

 Currant No. 5136; aDgle to symphysis 21; angle to condyle 235 ; angle to 

 coronoid process 2-25; posterior molar to coronoid process 1. 



Aluatta Beelzebul. 



Simia Beelzebul, Linn., Ed. xiii. 1*785, p. 35. 



Mycetes rufimanus, Kuhl, Beitrage, 1820, p. 31. 



Mycetes discolor, Spix, Sim. et Vesp., 1823, p. 48. 



Mycetes villosus? Gray, Ann. and Mag. of N. H., 1845, p. 220. 



Icon., Spix, T. xxxiv. 



Hub. Brazil, Paraguay. 



A. Nigra, pilis ad basin brunneis, manibus fuscis aut griseis. 



Black, slightly dashed with yellow on belly and on internal surface of limbs ; 

 hairs of body brown at their bases aad black at their apices; hands reddish- 

 I rown or grey. 



This species resembles at first sight the niger or young ursina, but may be 

 feadilv distinguished from the former by the brown tint of the bases of hair3 

 of body ; from the latter, by the length of the hairs and the total absence of the 

 reddish-brown at iheir apices, which is always present in that species. Much 

 stress has been laid on the coloration of the hands; this is very variable, being 

 in some specimens reddish-brown, in others greyish, and in others nearly black. 



* Is Qeoffroy St. Ililaire's paper, though dated subsequently to that of Humboldt, must hare been 

 i ib id anterior to it, and Humboldt quotes Stentor niger, Geoff, us a synonym. I have there- 

 itained Ueoffroy's name. 



[Nov. 



