INTRODUCTION. XVII 



elevations, effected posterior to their formation. 

 The experience derived from observations made 

 on the Cornish Coast, can of course be but of 

 little value, either as contradictory or confirma- 

 tory of such an opinion; yet it is proper to state 

 that Zoophytes of all the orders to be described 

 in the following pages have been procured from 

 about sixty fathoms water. Though they, there- 

 fore, may not extend to any great depth, yet 

 they are certainly not confined to thirty fathoms 

 of water as has been supposed. Algae, however, 

 are never found on the stones drawn from more 

 than twenty five fathoms, on any part of our 

 coast. 



In the following pages the term polypidom is 

 very frequently used, but it is synonimous with 

 polypier of continental Naturalists, and as only 

 a convenient mode of expression for the solid 

 parts of Zoophytes, such for instance as the 

 horny parts of Seriularice and the solid axis of 

 Gorgonia; beside this, no terms are used, which 

 require any explanation. 



