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1865. ] Indian Gasteropoda, 61 
laid down, on precisely the same grounds of certain: peculiarities in 
the distribution of Fish, which appeared to me (though unhappily 
not to Mr. Blanford) so convincing in the case of the Land Shells. of 
India. 
So-identical are the results and the proofs in either case, that I 
think it necessary to say, that till the present month, I had never seen 
the work I am about to quote from, or any writings whatever of either 
Gould or Agassiz, and that my views of the sporadic origin of certain 
species of shells were deduced from considerations touching their 
distribution, and in ignorance of similar arguments, derivable from the 
study of an entirely different class. 
The following quotation from page 211 of the Principles of Zoology 
will prove how closely the estimate I formed of the practical effects 
of accidental distribution, corresponds with that. held by Gould and 
Agassiz. 
“448, Other causes may also contribute towards dispersing animals. 
Thus the sea-weeds are carried about by marine currents and are 
frequently met with far from shore, thronged with little crustaceans 
which are in this manner transported to great distances from the 
place of their birth. The drift wood which the Gulf Stream floats 
from the Gulf of Mexico even to the western shores of Europe is 
frequently perforated by the Larve of insects, and may probably serve 
as depositories for the eggs of fishes, crustacea and mollusks. It is 
possible also that aquatic birds may contribute in some measure to 
the diffusion of some species of fishes and mollusks, either by the 
eggs becoming attached to their feet or by means of those which they 
evacuate undigested after having transported them to considerable 
distances. Still all these circwmstances exercise but a very feeble 
influence upon the distribution of species in general, and each country 
none the less preserves its peculiar physiognomy so far as its animals 
are concerned, 
“449, There is only one way to account for the distribution of 
animals as we find them, namely to suppose they are autochthonoi, 
that is to say that they originated like plants, on the soil where they 
are found. In order to explain the particular distribution of many 
animals, we are even led to admit that they must have been created at 
several points of the same zone, an inference which we must make from 
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