PREF AGE 
TO THE FIRST EDITION. 
Tue term * Malucology,’ an abbreviation of ** Malacozoo- 
logy,” from the Greek uaazzes, soft, Cwov, an animal, and 
Agyos, @ discourse, was first employed by the French naturalist 
De Blainville to designate an important division of Natural 
History, in which the leading feature of the animals dis- 
cussed was the softness of the flesh, or, to speak with greater 
accuracy, of the general envelop. This division compre- 
hends not only the Mollusca, but also the T'estacea of Aristotle 
and of Pliny, and, of course, had reference to molluscous 
animals in general—of which the greater portion have shells. 
A treatise concerning the shells, exclusively, of this greater 
portion, is termed, in accordance with general usage, a Trea- 
tise upon Conchology or Conchyliology ; although the word 
is somewhat improperly applied, as the Greek conchylion, 
from which it is derived, embraces in its signification both 
the animal and shell. Ostracology would have been more 
definite. cf 
The common works upon this subject, however, will ap- 
pear to every person of science very essentially defective, 
inasmuch as the relation of the animal and shell, with their 
dependence upon each other, is a radically important con- 
sideration in the examination of either. Neither, in the at- 
tempt to obviate this difficulty, is a work upon Malacology 
at large necessarily included. Shells, it is true, form, and, 
for many obvious reasons, will continue to form, the subject 
of chief interest, whether with regard to the school or the 
cabinet ; still there is no good reason why a book upon Con- 
chology (using the common term) may not be malacological 
as far as it proceeds. 
In this view of the subject the present little work is offered 
to the public. Beyond the ruling feature—that of giving an 
anatomical account of each animal, together with a descrip- 
