280 ISLAND LIFE 



since they are found in a considerable number of islands 

 which possess no mammals nor any other land reptiles ; 

 but Avhat those means are has not yet been positively 

 ascertained. 



It is unusual for oceanic islands to possess snakes, and it is 

 therefore somcAvhat of an anomaly that two species are 

 found in the Galapagos. Both are closely allied to South 

 American forms, and one is hardly different from a Chilian 

 snake, so that they indicate a more recent origin than in 

 the case of the lizards. Snakes it is known can survive a 

 long time at sea, since a living boa-constrictor once 

 reached the island of St. Vincent from the coast of South 

 America, a distance of two hundred miles by the shortest 

 route. Snakes often frequent trees, and might tlius be 

 conveyed long distances if carried out to sea on a tree 

 uprooted by a flood such as often occurs in tropical climates 

 and especially during earthquakes. To some such accident 

 we may perhaps attribute the presence of these creatures 

 in the Galapagos, and that it is a very rare one is indicated 

 by the fact that only two species have as yet succeeded in 

 obtaining a footing there. 



Birds. — We now come to the birds, Avhose presence here 

 may not seem so remarkable, but which yet present 

 features of interest not exceeded by any other group. 

 About seventy species of birds have now been obtained on 

 these islands, and of these forty-one are peculiar to them. 

 But all the species found elsewhere, excej^t one, belong to 

 the aquatic tribes or the Avaders which are pre-eminently 

 wanderers, yet even of these eight are peculiar. The true 

 land-birds are forty-two in number,^ and all but one are 

 entirely confined to the Galapagos ; Avhile three-fourths 

 of them present such peculiarities that they are classed in 

 distinct genera. All are allied to birds inhabiting tropical 

 America, some very closely ; while one — the common 

 American rice-bird which ranges over the whole northern 

 and part of the southern continents — is the only land-bird 

 identical with those of the mainland. The following is a 

 list of these land-birds taken from Mr. Salvin's memoir in 

 the Transactions of the Zoological Society for the year 1876, 

 to which are added nine species collected in 1888 and 



