History of Conckology . 255 



culate formation of the aperture of the shell gave an insig-ht into the 

 habits of the snail in regard to food ; the first too to point out fully 

 the influence of age and sex in altering the shape of the shell, and 

 more especially of its aperture ; the first to describe and delineate the 

 animal tenant of many genera ; and although his attention was ex- 

 clusively directed to external characters, yet we are above all in- 

 debted to him for his strong advocacy of the maxim that the anatomy 

 of the animal vvas the sole sure foundation of a rational arrangement 

 which had in view the mutual affinities of the objects it attempted to 

 classify, and present them not fancifully commixed as they might be 

 placed in a museum, but according to those characters which nature it- 

 self had given them of affinity or dissemblance. " There is then," he 

 says, '* in shell- fish something more to consider than their shells ; 

 the snail which tenants them ought to guide our methodical arrange- 

 ments, to be our only regulator, since it is the principal part, that 

 which gives to the exterior skeleton its form, size, hardness, colours, 

 and all the other peculiarities in it which we admire. If we atten- 

 tively examine this new and forgotten race, if we consider individual- 

 ly the members of it, we shall discover in their manners, in their ac- 

 tions, in their movements and manner of life, an infinitude of curious 

 circumstances, of facts interesting and fitted to arrest the attention 

 of every zealous and intelligent observer ; we shall perceive in the 

 organism of their bodies a great number of parts remarkable in their 

 structure and use ; and in entering into details we shall soon be com- 

 pelled to grant that this study is no childish play, but as thorny and 

 full of difficulties as any other in the wide range of natural history."* 

 The example of Adanson was followed by Geoffroy who, in a his- 

 tory of the shells found in the vicinity of Paris, attempted to arrange 

 them on the external anatomy of their animals ; and by Muller, who 

 described in the same manner the mollusca of the north of Europe. 

 The writings of Muller are still deservedly held in high estimation. 

 They contain the descriptions of many novelties, and his descriptions 

 of them, as well as of species previously known, are remarkable for 

 their accuracy ; they are thickly strewed with notices of the exter- 

 nal anatomy and habits of those he had examined alive ; and his style 

 of writing is interesting, rising occasionally to eloquence. As an ob- 

 server and teller of what he had observed, he claims a place among 

 the first, but he was the discoverer of no fact in their structure or 

 physiology of any consequence — we speak in reference to the mol- 

 lusca only ; and his systematic eff"orts were limited and partial, al- 



* Lib. sup. cit. pref. x. 



