THE GENEALOGY OF ANIMALS 93 



used. The hind-limbs in most seals stretch per- 

 manently out behind, the webbed digits spreading 

 out fan-shaped on either side of the stumpy tail, 

 and constituting a rowing apparatus functionally 

 homologous with the tail of fishes and whales. 

 According to Jordan, the fur seals and the hair 

 seals are descended from different families of land 

 carnivora, the former probably from the bears, 

 and the latter from the cats. 



The lemurs are of especial interest to human 

 beings, because in them are found the first startling 

 approximation in looks and structure to the 

 'human form divine.' The lemurs are monkey- 

 like creatures living in trees, but differ enough 

 from true monkeys to be often placed in an order 

 by themselves. Their milk glands are abdominal 

 instead of pectoral, as in the monkeys, and the 

 second digit of each hand and foot ends in a claw. 

 The most of them live in Madagascar. They are 

 generally nocturoal in their habits, although some 

 species are diurnal. They appear first in the 

 Eocene rocks, and Haeckel thinks they may have 

 developed from opossum -like marsupials in the 

 late Cretaceous or early Eocene Age. 



From lemurs or from some other similar sort of 

 semi-apes developed the true apes — the flat-nosed 

 (platyrhine) apes of the New World and the 

 narrow-nosed (catarhine) apes of the Old World. 

 There is considerable difference between the New 

 World apes and those of the Old World. The 

 differences between the two classes is, in fact, so 

 striking that they are thought by some to have 



