OF CONCHOLOGY. 25 



To resume, the system proposed for the Pulmonates, as well 

 as the one which applies to the rest of the Gasteropods, is, we 

 think, erroneous : 



1. Because it has the inconveniency of placing in different 

 families Mollusks allied by the shape of their shells, their prin- 

 cipal organs, their way of living, and all this to take for a basis 

 characters comparatively of little importance in the organism 

 taken as a whole. 



2. Because, even if we could admit theoretically, in classifi- 

 cation, the characters drawn from the lingual and buccal denti- 

 tion of the Mollusks, this manner of proceeding would be impracti- 

 cable on a large scale in the present state of our knowledge of 

 the science. And, indeed, it would be absolutely necessary to 

 propose a classification of that kind, reposing on a suliiciently 

 secure basis, to know first the buccal and lingual organization of 

 almost all the actual catalogued species, and not merely that of 

 an imperceptible minority, which renders every kind of serious 

 generalization impossible, or compels us to introduce hypotheses 

 in a science of observations. 



As for paleontology and fossil Mollusks, it is worse still,*for 

 there we find ourselves before a radical and perpetual impos- 

 sibility, seeing that of those species the shell only is or ever will 

 be known ; in such conditions the shell is then necessarily the 

 only possible base of any classification. 



Our conclusion is that, although nothing must be neglected in 

 matters of science, and that it is wise to make use of the new 

 documents which every day brings forth, it is dangerous to be 

 too exclusive, and to be obstinate enough to look at but one face 

 of science. The studies of the great anatomists have served to 

 reveal the intimate organization of Mollusks, and have given us 

 the means to delineate surely this important division of the animal 

 kingdom. The thorough study of the lingual and buccal denti- 

 tion is a recent conquest of science, whos^value must be acknowl- 

 edged, and of which it is wise to make use in a reasonable mea- 

 sure. But, is it a reason for discarding the previous characters 

 which is furnished, for the classification of Mollusks by the study 

 of the shell, considered in its complete structure, as well as in 

 its general appearance ? We think not, and we believe that the 

 serious and simultaneous study of these three kinds of characters 

 is not too much on which to base the foundation of a good clas- 

 sification of the Mollusca, for a classification can only be re- 

 cognised as such if it reposes, not only on one or two charac- 

 ters arbitrarily chosen, but on the organization of the animals 

 taken as a whole. 



