154 THE LOWER PRIMATES 



outspoken ieatures of the simian tribes. This relatively large family of new- 

 world primates, however, because of its convergences and divergences within 

 this order of mammals, should afford interesting evidence in the structure of 



Courtesy, AmeTtcan Museum of Natural History 



FIGS. 67 AND 68. CALLITHRIX JACCHUS (MARMOSET). 



its central nervous system and more particularly in the bram. The species 

 here described is Callithrix jacchus. The greater number of the species 

 included in the genus Callithrix are natives of Brazil, one species formerly 



