CLASSIFICATION. 91 
tute for knowledge, might eclipse the claims of that 
great man. But, when analyzed, they are found to be, 
in then* general outlines, essentially the same as the 
method proposed by him, the new one being merely a 
new nomenclature, with changes in the arrangement 
of the subordinate parts, and such new grouping of 
genera, as more recent anatomical investigations have 
rendered necessary. Some difference there is, also, 
in the opinions held concerning the comparative rank 
and value of the different sections, and the limits of 
the division itself, some authors including among the 
Mollusks one or more classes of animals which are 
excluded by others, and elevating to the rank of dis- 
tinct classes groups which, by others, are placed in the 
subordinate position of orders and families. With these 
changes and limitations, the primary subdivisions re- 
main as proposed by M. Cuvier in 1798, the minor 
parts having been from time to time modified by the 
labor of himself and other authors who have treated of 
these animals as a class. 
It is not intended, here, to give a particular account 
of the classification of the Mollusks as at present re- 
ceived, but it is essential to the correct understanding 
of our subject, so far to exhibit it, as to show the 
position which the animals described in this work 
hold, the peculiarities which characterize them as a 
body, and the relations which they bear to each other, 
and to the other families of the same type of organi- 
zation. No method of classification hitherto published, 
