152 SPECIAL FEATURES 



and are no doubt due to the fact that the chances of 

 the fish of one loch interbreeding with those of another 

 are very small. There are also a considerable number 

 of pecuKar species or varieties of insects, but nothing 

 comparable to the differences which separate the 

 animals of the Galapagos Islands from those of the 

 adjacent mainland. To add point to the contrast we 

 may note that the area of the British Isles is in round 

 numbers, 121,500 square miles, as contrasted with the 

 3,000 square miles of the Galapagos Islands. Suchislands 

 as the British Islands are called by Wallace continental, 

 in contrast with the oceanic type. 



One more example of an island faima may be given. 

 In this case we shall take Madagascar, which is of the 

 continental type, but is separated from the continent 

 of Africa by a channel so deep and wide that it must 

 be supposed that the connexion between the two was 

 broken at an extremely remote period. The total area 

 of this large island is nearly twice that of the British 

 Isles, and there is much forest. The fauna is remark- 

 ably rich, and is as markedly characterized by the 

 animals it includes as by those of which it is devoid. 

 Thus the island has no monkeys in its wide tropical 

 forests, but has some thirty-three species of lemurs, 

 which constitute half the mammalian population 

 of the island. Insectivores are fairly numerous, and 

 include in the tailless hedgehogs (Centetes) primitive 

 forms whose nearest aUies appear to be some shrews 

 in the West Indian Islands. There are not many 

 carnivores, and no true cats, but in addition to eight 

 civets there is a relatively powerful animal called 

 Cryptoprocta, about the size of a common cat, which 

 belongs to the civet group. There are few rodents, and 

 the enormous wealth of large ungulates, which is so 



