EVOLUTION OF THE HUMAN SPECIES 161 



to a more developed element of the animals placed in 

 the higher sections. 



The lemurs are small animals very much like squirrels 

 in their general form and in their tree-climbing habits. 

 They live now almost exclusively on the island of 

 Madagascar, but palaeontology shows that they were 

 more widely spread at an earlier time. Their teeth 

 are exactly like our own, except that there is one more 

 premolar on each side of each jaw. The '^ fingers" 

 and ^Hoes" bear nails like ours, again with an exception 

 in the case of the second digits of the hind limbs, which 

 bear claws. The details of structure that set these 

 animals apart from all the rest of the primates are too 

 small to deserve comment in the present connection. 



Passing to the true anthropoids, or man-like primates 

 and man himself, the first forms encountered are the 

 little marmosets, which are like the lemurs in some 

 ways, but in other respects they resemble the familiar 

 tailed monkeys. ' They are peculiar in having three 

 premolars and two molars on either side of both upper 

 and lower jaws, and also in the fact that the ''thumb" 

 is not opposable to the other fingers, while all the digits 

 except the ''great toes" bear claws instead of manlike 

 nails. The proportion of brain-case and face does not 

 differ much from that in the lemurs and even lower 

 forms like cats, for the brain has not increased greatly 

 ^JpQ total mass, though the cerebrum is more conv.oluted 

 than in the lower forms. 



The true monkeys, or Cebidae, are more interesting, 

 and at the same time they are much more familiar to 

 every one, as they are the commonest anthropoids of 

 the menagerie and circus. Their wonderful agility 



