SUPPLEMENTARY TREATISE 
ON THE 
MOLLUSCA. 
I. ON THE DIVISION IN GENERAL. 
IT is now five or six and twenty years since naturalists first 
so designated under the general name of MOLLUSCA a 
numerous portion of the Animal Kingdom, including not 
only the true mollusca of Aristotle and Pliny, but also the 
testacea of these ancient writers. 
This name, mollusca, comes from the Greek word paAaka, in 
Latin, mollia (soft), because the majority of the animals to 
which this denomination has been applied are remarkable for 
the softness of their flesh, or more properly speaking, of their 
general envelope. 
The science which treats of this portion of zoology has as 
yet received no peculiar name. Conchology, it must be re- 
membered, is applicable only to the investigation and arrange- 
ment of the shells of such of these animals as have them. 
M. de Blainville has proposed the name of malacozoology, 
or thus abbreviated, malacology, compounded of padakoc, 
Ewov, and Aoyog; that is to say, a scientific discourse or trea- 
tise on the soft animals. 
Aristotle, the most ancient and important of the natural 
