PART I. 



THE ECONOMY 



OF 



BRITISH 

 HYDROID ZOOPHYTES. 



General Remarks. ''Things of beauty 

 are generally small," says Aristotle, and the 

 animals here represented, taken individually, 

 are generally so minute that they would 

 probably escape the notice of even the most 

 enthusiastic searcher, did they only occur 

 singly. They, however, have the habit in one 

 of the phases of their existence — the fixed 

 phase— of living collectively or in colonies, 

 and in this form they may be discovered 

 without much difficulty, in rock pools along 

 the sea-shore ; growing amidst the groves and 

 spinneys of seaweed, or upon rocks, seaweed, 

 and shells ; they are also carried about on the 

 coverings of living shell-fish, upon the backs 



