INTRODUCTION. gg 



will continue to be, a most important auxiliary to the 

 elucidation of geology ; but without the reform we have 

 indicated, it cannot be much longer considered as a 

 branch of zoology. It must give way to the more philo- 

 sophical investigation of the mollusks as living beings, 

 whose organization and relations must occupy the atten- 

 tion which has hitherto been given to minute and com- 

 paratively unimportant particulars of the shell alone. A 

 pursuit which, under the name of a science, has often 

 served to give dignity to trifles, and which has caused 

 a false estimate of the character and importance of 

 all zoological studies, in the minds of many, will thus 

 fall to its proper level, and take its rank as one of 

 the scientific nugse which, in times past, have amused 

 the minds and occupied the learned leisure of its adepts. 

 Our successors will look back with astonishment to 

 the period when persons, busied with the collection, 

 arrangement, and classification of these external envel- 

 opes, often without the ability of distinguishing the 

 animal of one genus from that of another, and some of 

 whom, in a long career, never saw a single one of the 

 animals whose products they were so famiUar with, 

 were considered to be naturalists, when they were in 

 fact mere collectors. 



There is one excuse, however, which may be urged 

 for the very general reliance which has been placed 

 upon characteristics foimded on variations of the shell, 

 and that is, the prevalent idea, sanctioned by some 

 leading names, that every difference in the shell is 



