Lamarck’s Genera of Shells. 65 
his day, having shewn, that in a variety of instances, many 
shells which he had confounded together as species of one 
common genus, require to be separated into several distinct 
genera. Secondly, the establishing a system of conchology, 
on the characters of the shells, is in some measure to insulate 
the science, and to deprive it of half its charms, by disconnect- 
ing it, as it were, from the other branches of natural history, 
in all of which, it is the animal, and not his dwelling, that is 
the leading object. Why, in this solitary instance, is the living 
agent to be secondary to his own work? What should we say 
of the naturalist, who would class the beast by his den, or the 
bird by her nest? The external characters have a high value; 
they are always essential in forming species and often genera, 
but still they are subordinate, when the science is regarded as 
one link of the great chain of life, connecting the scarcely per- 
ceptible traces of animation in the infusorza, with the full de- 
velopement of its powers in the intelligence of man. 
Linnzus indeed makes conchology a part of his Systema 
Nature, constituting the third order of the class Vermes; but 
still, in his method of studying it, comparatively so little atten- 
tion is paid to the animal, as to render the science rather a 
lateral branch, than part of the main trunk of the system ; and 
we suspect that some modern cultivators of it, or rather col- 
lectors of shells, almost forget that any animals are at all con- 
cerned in the business. 
“ Some have endeavoured,” says the author quoted above, 
“* to found a system of conchology upon the inhabitant rather 
than upon the shell. This plan has indeed generally been 
acknowledged as theoretically just, but as uniformly discovered 
to be defective in the execution, on account of the utter im- 
possibility of procuring from the unfathomable recesses in which 
many, if not the majority, abide, a sufficient number of live 
and perfect specimens. 
“« Of those which are more readily attainable, there are parts 
and habitudes very difficult to be accounted for, which yet may 
constitute an essential difference in the animal. Were we in- 
deed able to obtain the inmates of every known shell, and sub- 
