232 THE GEOGRAPHY OF MAMMALS 



kind of distribution few instances are known amongst 

 mammals, but many somewhat similar cases have been 

 observed in birds, reptiles, and butterflies. 



The fourth and lowest sub-family of the Cebidse 

 (Nyctipithecinse) includes three genera — the Douroucoulis 

 (Nyctipithecus), the Titis (Callithrix), and the Squirrel- 

 Monkeys (Chrysothrix), and numbers altogether some 

 twenty species. This group, as a whole, has a wide range 

 like the two first sub-families, extending from Central 

 America to Paraguay. But the species are most abun- 

 dant in the centre of the area, where some of them, so far 

 as is yet known, have a very limited range. 



Section V. — Distribution of the Marmosets 



Like the Platyrrhine Monkeys the little Marmosets, 

 which constitute the family Hapalidte, are entirely re- 

 stricted to the tropical forests of the New World. The 

 family embraces but two genera generally acknowledged — 

 Hapale with about seven, and Midas with about fourteen 

 or fifteen species. But these small creatures are still little 

 known, and it is probable that many more of them remain 

 to be discovered when the vast forest-region through 

 which they are distributed shall have been more thoroughly 

 explored. The Marmosets do not extend so far north as 

 the true Monkeys, only a single species (Midas geoffroyi) 

 having yet been ascertained to range north of the Isthmus 

 of Panama as far as Chiriqui. Thence, southwards, they are 

 thinly distributed over the South American continent down 

 to the northern provinces of the Argentine Kepublic, where 

 Hapale penicillata is said to occur in the forests of Salta 



