50 ESSAY ON CLASSIFICATION. Part I. 



Wonns, the Earthworms and Leeches furnish a still wider range of comparisons 

 when contrasted with the marine types. Among Gasteropods and Acephala, this 

 obtains to the same extent ; tlie most gigantic Ampullariae and Anodontae are small 

 in comparison to certain Fusus, Voluta, Tritonium, Cassis, Strombus, or to the 

 Tridacna. Among Radiata even, which are all marine, with the exception of the 

 single genus Hydra, this rule holds good, as the fresh water Hydroids are among the 

 .smallest Acalephs known. 



This coincidence, upon such an extensive scale, seems to be most favorable to 

 the view that animals are modified by the immediate influence of the elements; 

 yet I consider it as affording one of the most striking proofs that there is no causal 

 connection between them. Were it otherwise, the terrestrial and the aquatic repre- 

 sentatives of the same family could not be so sunilar as they are in all their 

 essential characteristics, which actually stand in no relation whatsoever to these 

 elements. What constitutes the Bear in the Polar Bear, is not its adaptation to an 

 aquatic mode of existence. What makes the Whales Mammalia, bears no relation to 

 the sea. What constitutes Earthworms, Leeches, and Eunice members of one class, 

 has no more connection with their habitat, than the peculiarities of structure which 

 unite Man, Monkeys, Bats, Lions, Seals, Beavers, Mice, and Whales into one class. 

 Moreover, animals of different types living in the same element have no sort of 

 similarity, as to size. The aquatic Insects, the aquatic MoUusks fall in with the 

 average size of their class, as well as the aquatic Reptiles and the aquatic Birds, or 

 the aquatic Mammalia ; Init there is no common average for either terrestrial or 

 aquatic animals of different classes taken together, and m this lies the evidence that 

 organized beings are independent of the mediums in which they live, as f\ir as their 

 origin is concerned, though it is plain that when created they were made to suit 

 the element in which they were placed. 



To me these facts show, that the phenomena of life are manifested in the 

 physical woi'ld, and not through or by it; that organized beings are made to 

 conquer and assimilate to themselves the materials of the inorganic world ; that 

 they maintain their original characteristics, notwithstanding the unceasing action of 

 physical agents iqjon them. And I confess I cannot comprehend how beings, so 

 entirely independent of these influences, could be produced by them. 



