1S65/J 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 Grould 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 G-ulf Stream floats 

 from the Gulf of Mexico even to the western shores of Europe is 

 frequently perforated by the Larvge 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 circumstances exercise but a very feeble 

 influence upon the distribution of species in general, and each country 

 none the less preserves its pecidiar 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 mast make from 

 9 



