INTRODUCTION. 
Notwithstanding the information of celebrated 
voyagers and philosophers, much yet remains un- 
known of those Polypidoms which people the vast 
empire of the deep ; a very small number of their 
polypi have been observed, and entire orders still 
exist, whose animals have not to this moment been 
discovered : no light has been thrown on their orga- 
nization, their growth, or their continuance ; all yet 
remains in obscurity respecting the physiology of this 
singular class of organization ; but that they are 
wholly animal, remains no longer a doubt, and the 
term Zoophyte, though still used, becomes, from its 
signification of animal plant, not strictly applicable. 
The Polypidoms present no character so decided, 
as serving for habitation, and forming the most solid 
