CEBTDM. — PITHECIA. 27 



Siamiris ustus. 

 Tsid. Geoff., Voy. de la Venus, p. 96, pi. 2. figs. 4, 5 (skull), 1855. 



OUAKARIA. 



Teeth: — Incisors^; Canines j^jj Premolars -j^j ; Molars — ; =36. 



Ouakaria calvus. 



Cervical vertebrae 7 



Dorsal 13 



Lumbar 6 



Sacral 3 



Caudal 18 



*a. Skull. Near the River Amazon. Presented by M. E. Bourcier. 

 b. Skeleton. From Mr. Bartlett's Collection. 



Ouakaria spixii. 



Cervical vertebrae 7 



Dorsal 13 



Lumbar 6 



Sacral 3 



Caudal 18 



a. Skeleton. Presented by the Zoological Society. 



PITHECIA. 



Teeth: — Incisors |f?; Canines j^i; Premolars || ; Molars ™ ; =36. 



The Whiskered Yarke. Pithecia pogonias. 

 *«. Skull : very young. From Mr. Bartlett's Collection. 



The Yarke. Pithecia irrorata. 

 *«. Skull. Rio Negro. From Mr. Stevens's Collection. 



Pithecia ? 



a. Skull. Rio Negro. From Mr. Stevens's Collection. 



Pithecia albicans. 



*or. Skull. Upper Amazons. 



NYCTIPITHECUS. 

 Teeth:— Incisors £|j Canines j^-j : Premolars^': Molars f^;=36. 



