302 ORIGIN OF LIFE IN AMERICA 



to the above-mentioned Hawaiian forms, is merely a super- 

 ficial one, and not indicative of real relationship. Drs. Roth- 

 schild and Hartert, indeed, believe that this is the case, but 

 as a certain affinity between these widely separated islands 

 undoubtedly exists in some other groups, Mr. Ridgway's view 

 may possibly turn out to be the correct one. Moreover, as 

 Mr. Ridgway points out, two of the Hawaiian Procellariidae, 

 viz., Aestrelata phaeopygia and Oceanodroma cryptoleucura 

 occur in the Galapagos islands. 



Drs. Rothschild and Hartert * derive the whole avifauna 

 from America. All the same, their studies do not lead them to 

 adopt Darwin's theory. They remain uncertain whether the 

 fauna points to a former land connection with the mainland 

 or whether it owes its existence to accidental dispersal. That 

 there should be this doubt in their minds is rather surprising, 

 considering their own statement that the geological evidence 

 is entirely opposed to the theory of a former land bridge be- 

 tween the islands and America. 



The most recent study on the birds of the Galapagos archi- 

 pelago is that of Messrs. Snodgrass and Heller, f Taking 

 the general results of all these papers, there can be no 

 doubt that the avifauna is mostly related to South and Central 

 America and the West Indies, thus agreeing in that respect 

 with the mammalian fauna. 



The reptiles of the Galapagos islands certainly offer the 

 greatest difficulty to the acceptance of Darwin's theory that 

 the islands have risen from the floor of the ocean and have 

 never been connected with one another or with the continent. 

 Darwin observed only one small lizard belonging to a South 

 American genus, two different kinds of the great lizard 

 Amblyrhynchus a genus confined to the islands one kind 

 of snake and a land tortoise. He noticed that the one kind of 

 Amblyrhynchus lived altogether on land, the other being 

 semi-aquatic. The latter he described as a hideous looking 

 black creature up to four feet in length, with a laterally 

 flattened tail and webbed feet. Sluggish in their movements 

 on shore these huge lizards are expert swimmers, darting 



* Rothschild, W., and E. Hartert, " Ornithology of the Galapagos 

 Islands," pp. 137139. 



t Snodgrass, E. E., and E. Heller, "Birds of the Galapagos Islands." 



