ZOOLOGY. 311 



locality, in order to meet with all the different kinds. I sub- 

 join a list of the species, with the localities in which they were 

 found. 



MONKEYS FOUND ON THE AMAZON AND THE RIO NEGRO. 



i. Mycetes seniculus, Geoff. ; on the Rio Negro and the 

 north bank of the Amazon. 



2. Mycetes caraya, Gray ; on the Upper Amazon 



3. Mycetes beelzebub, Br. Mus. ; Para. 



4. Lagothrix Humboldtii, Geoff. ; Upper Amazon and west 

 of Rio Negro. 



5. Ateles paniscus, Geoff. ; Guiana, north bank of Amazon 

 and east of Rio Negro. 



6. Cclnis apella, Erxk (?) ; Amazon and Rio Negro. 



7. Ccbus gracilis, Spix ; Rio Negro and Upper Amazon. 



8. Callithrix sciureus, Geoff. ; the whole Amazon valley. 



9. Callithrix torquatus (amidus, Geoff.) ; Upper Rio Negro. 



10. Callithrix personalis, Geoff. ; south bank of Upper 

 Amazon. 



11. Nyctipithecus trivirgatus, Humb. ; Upper Rio Negro. 



12. Nyctipithecus felinus, Spix ; Upper Amazon. 



13. Pithecia irrorata (hirsula, Spix) ; south bank of Upper 

 Amazon. 



14. Pithecia , north of Upper Amazon. 



15. Brachiurus satanas, Br. Mus.; Guiana, east bank of 

 Rio Negro. 



16. Brachiurus oakary, Spix ; Upper Rio Negro. 



17. Brachiurus rubicundus, Isid. ; Upper Amazon. 



18. Brachiurus , south side of Upper Amazon. 



19. Jacchus bicolor, Spix; north of the Amazon and Rio 

 Negro. 



20. Jacchus tamarin, Br. Mus. ; Para. 



21. Jacchus n.s., Upper Rio Negro. 



Of the above, the first seven have prehensile tails, a character 

 only found among the monkeys of America. The howlers, 

 forming the genus Mycetes, are the largest and most powerful. 

 They have a bony vessel situated beneath the chin, and a strong 

 muscular apparatus in the throat, which assists in producing the 

 loud rolling noise from which they derive their name, and 



