222 GLIMPSES OF NATURE. 



hours. On islands like the Azores, far removed from 

 a mainland, and having had no original connection with 

 any continental region, there are, accordingly, no 

 native quadrupeds and no native frogs, toads, or newts 

 to be found. 



It is different with reptiles. Many of these animals 

 are good swimmers, and we must also take into account 

 the fact that their eggs may be conveyed on driftwood, 

 and may be thus transported to far distant lands. There 

 exists an interesting problem of this latter kind in 

 connection with the Galapagos Islands. These form 

 a group of volcanic islands, erupted into the Pacific 

 Ocean, and lying about 600 miles off the South American 

 coast. Around them the sea is about 1000 fathoms 

 deep, and between the islands and the American coast 

 the depth may reach 2000 or 3000 fathoms. This is 

 a clear proof even if we had not their rock structure 

 to confirm the opinion that the Galapagos Islands 

 are the products of volcanic action, and are original 

 lone masses of land, showing no relation whatever to 

 the nearest continent. 



Now, on the Galapagos there are no native quad- 

 rupeds (mammalia) and no native frogs ; this fact is 

 justified by our scientific expectations, as we have seen. 

 There does exist on these islands a kind of mouse, the 

 true history of which is undoubtedly that of conveyance 

 by man to the Galapagos. But as regards the reptiles, 

 the case is very different : there are land-tortoises, 

 lizards, and snakes. The lizards number five distinct 

 species ; but all are of American origin, and find their 

 nearest relatives on the adjacent continent. One of 

 the Galapagos lizards is decidedly aquatic in its habits, 

 and is found swimming freely in the sea, feeding on 

 the seaweed of the island-coasts. 



