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On the Value of the Shells of Mollusca, for the purpose of 

 distinguishing Species and Higher Groups. By Professor 

 C. B. Adams. 



The following remarks contain little that is new ; on the 

 contrary, their object will require allusion to very familiar 

 facts. For this, I hope that a sufficient apology may be 

 found in the, at least, apparent diversity of views which exist 

 in relation to this subject. 



On the one side, conchologists are said to have no regard 

 to the inhabitants of the shells which they admire ; on the 

 other hand, a heterogeneous class of writers publish their 

 own opposite opinion that shells are of no more consequence 

 in natural history than the fur of quadrupeds, or even the 

 clothing or houses of men. 



We cannot avoid an expression of dislike to the phrase 

 " inhabitants of shells," as applied in science to Mollusca. 

 There would be an obvious propriety in it, if applied to her- 

 mit crabs (Paguridse), since they have no organic connection 

 with the shells which they occupy. But there is such a con- 

 nection between the soft parts and the shell of a Mollusca, 

 that neither alone constitutes an individual being, but the 

 whole together constitutes one animal. It would be no more 

 absurd, in scientific language, to denominate birds the inha- 

 bitants of feathers, and mammals the inhabitants of fur or 

 wool, &c. The term " the animal," which is frequently used 

 for the soft parts only, is liable to the same objection, — that 

 these parts alone do not constitute an animal. We fully 

 admit, however, the propriety of these terms as figurative 

 language, and would therefore by no means entirely discard 

 them. 



A writer in the Zoological Journal of London has consi- 

 dered the question. Whether the shell or " the animal" is 

 entitled to the name of the species ? and suggests that two 

 names are necessary ! This would be like giving one name 

 to the bones and another to the flesh of a quadruped. But 

 whether we call a skeleton a mammoth, or apply a specific 

 name to a shell, there is no danger of being misunderstood ; 



