12 
INTRODUCTION. 
lately doubted ; and because the Sepia has shewn 
the power of leaving, though not of returning, at 
pleasure to its receptacle, it has been considered a 
mere parasite. Till the right owner shall have been 
discovered, or it shall have been proved that the 
tenant uniformly found in possession could not be 
the builder, we may be pardoned for adhering to 
the old prejudice. 
Before we proceed to the systematic arrangement 
and explanation of the Genera, it will be necessary 
to acquire some knowledge of Terminology, as 
without this their technical descriptions will be un- 
intelligible. 
The terms expressive of the forms and characters 
of the Univalves are placed first in the following 
Catalogue, in conformity with the order adopted by 
the author of the ‘‘ Fundamenta Testaceologise 
in the Amoenitates Academicee ” of Linnaeus, 
from whence most of them are derived. 
