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 nugce 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 familiar 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 founded on variations of the shell, 
and that is, the prevalent idea, sanctioned by some 
leading names, that every difference in the shell is 
VOL. I. 19 
