INTRODUCTION 
Lamarck ’S System of Conchology, which is contained in his “ Histoire 
Naturelle des A nimaux sans Vertbbres” is now almost universally adopted 
among Naturalists; but that work being destitute of Graphic Illustrations, 
is rendered exceedingly difficult of comprehension to those who are not inti- 
mately acquainted with the science. The only means which are given for its 
attainment are written descriptions and numerous references to voluminous 
and expensive works: the former are frequently rendered inefficient, from 
the minute distinctions that characterize many of the genera ; and the latter 
are seldom available, the works referred to being difficult of access to the 
student. It is the object of the present Elementary Treatise to remove 
these difficulties, by presenting a concise description of the various Classes, 
Orders, Families, and Genera composing the System, accompanied with Illus- 
trations of characteristic and generally well known Species, drawn from na- 
ture, either from my own Cabinet or from those of obliging friends, and, 
w here it has not been possible to meet with specimens, from the best printed 
authorities. 
This work being chiefly graphic, I have purposely omitted the various 
classes of animals, having found it impossible to supply the requisite in- 
formation; but descriptions of them will be found in Lamarck’s Histoire 
Naturelle, before mentioned, or in Dubois’ Epitome of Lamarck’s Arrange- 
