300 
ORIGIN OF LIFE IN AMERICA 
Lasiurus has likewise succeeded in reaching one other group 
of islands besides the Galapagos archipelago, namely the 
Sandwich islands. The latter are inhabited by Lasiurus 
semotus, which is peculiar to them, and cannot therefore be 
considered as a recent human importation. 
Our present knowledge of the mammalian fauna of the 
Galapagos islands has added one factor of extreme importance 
to those hitherto known, namely the certainty that there are 
indigenous mammals on the archipelago. For this reason the 
Galapagos islands should be excluded from the oceanic 
islands, and be placed among the islands which once formed 
part of a larger land-mass or continent. It is not certain, 
however, that Darwin and Wallace would have taken that view, 
even had they been convinced that the mammals alluded to 
were truly indigenous in the islands. Some naturalists hold 
that even mammals can be successfully transported across 
the ocean on tree trunks and floating islands. Dr. Stearns,* 
in alluding particularly to the Galapagos fauna, remarks 
that a single tree of large size might carry with it not only 
molluscan and insect life, but also living individuals of many 
vertebrate forms that found refuge or safety upon it. Thus, 
he continues, if the environmental conditions were at all 
favourable, colonies of many animal forms could be trans¬ 
planted to distant regions. The possibility of such an acci¬ 
dental transportal must have been carefully considered and 
rejected by Darwin and Wallace. The Humboldt current I 
alluded to as striking the Galapagos islands does not come 
from the coast of Ecuador nor from Central America. It 
originates in the far south, and, passing northward, skirts the 
coast of Chile and southern Peru, and then leaves the land in a 
north-westward direction. The tree trunks spoken of by Dr. 
Stearns as carriers of all kinds of animal life would have had 
to travel several thousand miles, no doubt experiencing stormy 
weather on the way, before they could have safely deposited 
their loads of vertebrates on the shores of the Galapagos 
islands. If these floating trees are responsible for the present 
mammalian fauna of these islands, how is it that they have 
brought nothing new to them since their occupation by man ? 
* Stearns, E. E. C., “ Mollusk-fauna of the Galapagos Islands,” p. 3G6. 
