536 



THE CHANGING WORLD 



being very much shortened, thus allowing the large laterally placed 

 eyes to swing around in front into a spectroscopic position. When 

 this curious animal wishes to look behind itself, instead of rotating the 



eyeballs, its whole head swivels 

 around in an alarmingly weird 

 and dislocated manner. Mem- 

 bers of this genus are the only 

 primates with a single incisor 

 tooth in each half of the lower 

 jaw, other primates having two. 

 Their fingers and toes are much 

 elongated and terminate not only 

 with nails instead of claws, but 

 also with adhesive disks, which 

 are very useful in arboreal life. 

 On account of their long fingers 

 they are decidedly hand-feeders, 

 and are also able to take hold 

 of objects and to bring them up 

 close to their staring eyes for in- 

 spection, while with the hind legs, 

 adapted for hopping and spring- 

 ing from limb to limb, they some- 

 what resemble miniature kangaroos in their movements. According 

 to some authorities, these grotesque little animals- are a direct link in 

 the evolutionary chain leading to man, while other lemurs, monkeys, 

 and apes are held to be side deflections from the main line. The 

 possible relationship of Tarsius to mankind is based mostly upon 

 anatomical evidence, too technical to be enlarged upon here. The 

 interested reader is urged to look beyond the pages of this book for 

 further details. 



Monkeys form two great groups, those in the New World being 

 more primitive than their Old World relatives. The New World 

 broad-nosed (platyrrhine) monkeys do not have an opposable thumb, 

 but are partly compensated for this handicap by possessing a pre- 

 hensile tail that serves them as a fifth hand in their aerial adventures 

 in the tree-tops. They have a generous mouthful of thirty-six teeth. 

 Marmosets are the smallest of the New World monkeys, and 

 "howlers," the prima donnas of American tropical forests, are the 

 largest, with spider monkeys, capuchins, and other species inter- 



Tarsiiis, the goggle-eyed lemur which 

 arrests the attention of anthropological 

 ancestor hunters. 



