OF CONOHOLOGY. 17 



ON THE ERRORS OP TOO EXCLUSIVE CLASSIFICATIONS. 



BY H. CROSSE. 



Translated from the " Journal da. Conchyliologie," VI, No. 3, July, 1866. 



BY FRANK DAULTE. 



Ancient authors have proposed for those inferior animals, act- 

 ually known as MoUusks, systems of classification, which had the 

 fault of being founded on characters too exclusively conchological. 

 Beside, it could scarcely be otherwise at a time when the study 

 of these animals was so incomplete, that it did not always permit, 

 in separating or uniting them, a reliance on the specific charac- 

 ters of their internal organization. This has been the origin of 

 many errors, corrected since, and under whose influence, taking 

 for a base similarities more apparent than real, animals which 

 nature had separated from each other by important organic mo- 

 difications had been methodically put together. Thus, for exam- 

 ple, the Janthina has been confounded with the Helices, and 

 Halia Pria7nus has successively been considered as a Buccinum, 

 Bulla, Helix, and Achatina, before taking definitively the place 

 ascribed to it in classification by the organization of its Mol- 

 lusk as it is actually known.* 



The same reproach could not assuredly be made, without in- 

 justice against the most part of modern naturalists, as to ancient 

 authors, for the former seem to have systematically neglected 

 characters drawn from the intimate conformation and structure 

 of the shell, thus forgetting that they fall from one excess into 

 another, and that in so acting they deprive themselves volun- 

 tarily of precious information and important characters. 



We shall indicate two groups of naturalists, or, more correctly, 

 two schools who, we think, follow this system with a certain de- 

 gree of exaggeration. 



The first, which we shall designate under the name of School 



* The anatomy of Halia Priamus was published for the first time in the 

 •'Journal de Conchyliogie," Vol. VII, p. 158, pi. V. 



9 



