GEOGRAPHICAL DISTRIBUTION 423 



Mammals, and also the Elephants of the African continent are 

 conspicuous by their absence. 



Mascarene Birds (Aves). — The power of flight possessed by 

 most members of this class to a large extent prevents the evolu- 

 tion of peculiar species by isolation, and we must not therefore 

 expect the land-birds of Madagascar to be so characteristic as 

 the mammals, though it is sufficiendy striking to find that out of 

 238 species no less than 129 are limited to the island, and these 

 include representatives of 35 peculiar genera. We may take as 

 examples two species (of Philepitta) of great beauty, allied to 

 the Ground-Thrushes, though constituting a distinct family, and 

 four kinds of Fruit-Pigeon belonging to a genus {Alectorocenas) 

 only represented in Madagascar and some of the smaller islands 

 of the sub-region. 



Fauna of St. Helena. — This typical oceanic island, iioo 

 miles distant from Africa and 1800 miles from South America, 

 may be taken here as a good illustration of its class. Never 

 having formed part of a continent its indigenous fauna naturally 

 presents a strong contrast with that of Madagascar, being en- 

 tirely made up of such forms of life as have been able to reach 

 it by natural agencies. And since a broad stretch of sea is an 

 insuperable barrier to animals of many kinds, the faunistic char- 

 acters of St. Helena are largely negative, as in all other such 

 cases. On the other hand, the effect of isolation has been very 

 great, and a large proportion of the species are peculiar. 



St. Helena possesses no native Mammals, Land Birds, Rep- 

 tiles, Freshwater Fishes, or Freshwater Molluscs. There is, 

 however, one peculiar species of Plover [yEgialitis Sandce- 

 Helencs) allied to one native to South Africa. Of Land-Snails 

 twenty appear to be indigenous, if we include thirteen that have 

 become extinct in recent times. The Beetles (Coleopterd) of the 

 island have been studied with greater care than any other group 

 of insects, and 129 species are native to the island, to which all 

 except one of them are absolutely restricted. More than two- 

 thirds of these beetles are weevils, and, considering the boring 

 habits of such creatures, it is highly probable that the remote 

 ancestors of many of them were conveyed to St. Helena by the 

 agency of drift-wood. 



There can be no doubt that many of the animals originally 

 native to this island have become extinct as the result of human 



