PEEFACE. 
IX 
the curious ; and the details are more easily followed 
out^ from the very fact of the facility of observing 
many specimens at the same time^ in different states 
of development : so that^ to the philosophical concho- 
legist and reflecting student, the most common speci- 
mens may do more to illustrate the perfection and 
all-seeing wisdom of the Creator, than the most costly 
collection. In the description of the species, parti- 
cular attention has been paid to dividing them into 
small groups, to facilitate their determination ; and an 
attempt has been made to point out the different 
varieties that occur, not by describing each individual 
variety that may be found, but by indicating the 
points that have been observed to be most liable to 
variation, and also the monstrosities which, from the 
mode of formation of the shell, and some peculiarities 
in the habit of the different species, are likely to 
take place in each of them. To illustrate the animals 
of the different families and genera, a series of vig- 
nettes has been given ; and further to assist in deter- 
mining the species, some wood-cut figures of different 
parts of the animal, as the jaws, teeth, operculum, 
&c. &c., and of the shells, have been interspersed in 
the text. 
All the new species introduced into the work, and 
the more remarkable varieties, have been figured, 
and added to the plates (except Vertigo angustior^ 
which could not be procured) ; and the whole of the 
figures which were given in the former edition have 
