1 94 E VOL UTION OF TO-DA Y. 



fauna and flora is thus characterized by being strict- 

 ly American, and, with the exception of two or 

 three exceptional species, can be readily explained 

 by the ease with which animals and plants can reach 

 these islands during storms and high winds. 



The second example we will notice is the Gala- 

 pagos islands. They are situated at about the same 

 distance from South America that the Bermudas 

 are from North America, but with one important 

 difference. They are in the quiet Pacific where vio- 

 lent storms are almost unknown, and where even 

 strong winds are of rare occurrence. They are, 

 therefore, practically much more removed from the 

 mainland than are the Bermudas. This is further 

 proved by the fact that visits from the continent 

 are very rare ; the only actual cases known are a few 

 water-birds. The isolation is, therefore, much more 

 complete. Here as in the Bermudas there are no 

 mammals except rats, even the bats not having 

 succeeded in reaching the island. The rats are 

 doubtless derived from ships which have touched 

 here. Reptiles are, however, quite abundant. 

 There are two tortoises, five lizards, and two snakes. 

 Just how these animals succeeded in crossing the 

 water it is of course impossible to say. It is known, 

 however, that reptiles do possess some power of mi- 

 gration across the ocean. A living boa-constrictor, for 

 instance, has been known to have reached St. Vin- 

 cent Island, two hundred miles from South America. 

 That these Galapagos reptiles were derived from 

 the mainland, is plainly indicated by their close 

 relationship to the species now living in the conti- 



