v1 PREFACE. 
account has been given of the habits of each 
well-known species of our Land and Fluviatile 
Mollusca; and whilst the scientific character of 
the work has been uniformly sustained, all 
unnecessary complexities have been carefully 
avoided. 
The classification adopted is that which is 
employed by modern Zoologists. The specific 
terms are those that have been long familiar to 
home Naturalists. A few changes, however, 
have been introduced, consisting in the restora- 
tion of the older and equally well-known names. 
The generic name Helicella is substituted for 
that of Zontes, the latter name having been 
generally, but erroneously, used in place of the 
former. 
