302 
ORIGIN OF LIFE IN AMERICA 
to the above-mentioned Hawaiian forms, is merely a super¬ 
ficial one, and not indicative of real relationship. l)rs. 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. 137—139. 
t Snodgrass, R. E., and E. Heller, “ Birds of the Galapagos Islands.” 
