308 The American Naturalist. ~ (April, 
emerge from the sea can only be peopled accidentally, and must 
have a disharmonic flora and fauna. This is seen in all such 
islands, like the coral islands, which originated in this way. But 
in the Galapagos we found absolute harmony. Besides that we 
would have the greatest difficulty in explaining the presence of 
such peculiar forms as the gigantic land tortoises and the large 
lizards and the snakes, and so on; and again we would have the 
greatest difficulty to explain the peculiar distribution of the forms, ~ 
and their peculiar differentiation on the more peripheral islands. — 
To take only one example, how is it imaginable to explain the 
presence of these gigantic tortoises, some of which reach a weight 
of 700 pounds? They have not been introduced by man. When 
the islands were discovered by the Spaniards in the sixteenth cen- 
tury they were present in enormous numbers, like the other ani- 
mals. According to the elevation theory we can only think of 
an accidental importation of these tortoises by some current, be- 
cause they are quite unable to swim. After the islands had been 
elevated from the sea, and some vegetation had found its place 
there, it happened once, by a peculiar accident, that a land tortoise 
was carried over to the island. Alone it was helpless; it could 
not propagate. This was only possible after a similar accident 
imported another specimen of the same species, of the other sex, to 
the same island. Or we could imagine that at the same time 
animals of both sexes were thus accidentally introduced. By this 
we could at least explain the population of a single island. Bot l 
how did all the other islands become populated? To explain this — 
we would have to invoke a thousand accidents. But how can wê 
explain that the members of one genus reached all the islands, — 
_ and again those of another genus all the islands? ow can cee 
explain that each island has a peculiar form of these genera? 
With one word, how can we explain the harmony of distribution i 
the theory of elevation? All this is simply unexplainable by this 
theory. a 
The theory of subsidence, however, explains every point inato 
absolutely easy manner. All islands were connected together_at 
a former period ; at this time the number of species must bar 
been small ; through isolation the peculiar specialization of the 
