12 INTllODUCTION. 



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- 

 intellioible. 



The terms expressive of the forms and characters 

 of the Univalves are placed first in the following 

 Catalogue, in conformity w ith the order adopted by 

 the author of the " Fundamenta Testaceologise " 

 in the " Amccnitates Academicae " of Linnseus, 

 from whence most of them are derived. 



