560 DOROUCOULIS . CHAP. 
—— 
that of Mycetes. Nevertheless Professor Weldon! has found in 
a female of C. gigot 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. 
Nyctipithecus, 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 Chrysothria, but not as in Callithriz, 
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 Bb. calvus, 
way: 
Fig. 266.—Red-faced Ouakari. Brachyurus rubicundus. x4. 
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 Cebus and Pithecia. The 
1 “‘Notes on Callithrix gigot,” Proc. Zool. Soc. 1884, p. 6. 
2 Forbes, Proc. Zool. Soc. 1880, p. 639. 
