560 



DOROUCOULIS 



CHAP. 



that of Mycetes. Nevertheless Professor Weldon 1 has found in 

 a female of C. yigot a patch of ossification on the thyroid cartilage 

 of the larynx which may be an indication of something more in 

 the male. There are eleven species. 



NyctipithecAis, the Doroucouli Monkeys, is a genus of some- 

 what Lemurine appearance, caused by their large eyes. But they 

 reminded Bates of an Owl or a Tiger-cat ! They have a long, but 

 not prehensile tail. As in the Marmosets, the lower incisors 

 project forwards in a Lemurine fashion. The thumb is very 

 short. A peculiarity of this genus is the twenty- two dorso- 

 lumbar. vertebrae. As in Chrysothrix, but nut as in Callithrix, 

 the hemispheres of the brain are smooth. There are five species, 

 of which one occurs so far north as Nicaragua ; the rest are 

 Brazilian, extending down to the Argentine. 



The Ouakari Monkeys, Brachyurus? are, as the name denotes, 

 short -tailed forms. Two species, B. rubicundus and . calvus, 



FIG. 266. Red-faced Ouakari. Brachyv.rus rubicundus. x i. 



have bright red faces ; B. melanocephalus has a black one. 

 There is a small thumb. The brain is fairly convoluted, and is 

 to be specially compared with that of Celus and Pithecia. The 



"Notes on Callithrix gigot," Proc. Zool. Soc. 1884, p. 6. 

 2 Forbes, Proc. Zool. Soc. 1880, p. 639. 



