80 ZOOPHYTES. 



ceedingly obtuse, imperfect, and limited, farther than seizing and raven- 

 ously devouring whatever prey they can master. From this, perhaps, 

 they are always of small dimensions, when recovered from the sea. But, 

 by plentiful supplies of food, and frequent renewal of their native element, 

 they may be infinitely enlarged ; and they can be preserved several 



years. 



With age and increment the figure of the animal is considerably 

 modified, then becoming more elongated in proportion to its extreme dia- 

 meter. A colony under temporary abstinence is beheld in the most inte- 

 resting form, displaying so many pencils waving like tresses among the 

 water. 



The peculiar habitation of the trumpet hydra seems the inner surface, 

 and especially the upper cavity of empty oyster or other bivalve shells. If 

 to be identified with the Hydra gelatinosa of Miiller, a colony occurred to 

 that distinguished naturalist on the under side of a marine fucus. 



The oyster is very abundant in some parts of Scotland. The suspen- 

 sion of the hydra in its shell, together with intercepted view from the 

 profuse vegetation fringing the edges of many, may account for it so long 

 escaping the notice of observers. It difluses any where, however, pro- 

 vided the position be favourable, and certainly best where pendent under 

 shelter. It is obvious that a great colony on the lower valve of a large 

 shell, afterwards described, must have been most likely preserved from 

 some peculiarity, such as the shell resting at an inclination so as to allow 

 the action of the tentacula. 



Notwithstanding all this, it will be seen in the course of the follow- 

 ing narrative, that the position of the original founder of the colony must 

 be accidental, times out of number ; and that the dispersion of the pro- 

 geny is dependent on the place of the parent. 



The shell of a serpula bearing a group of hydrse was detached from 

 its fixture on an old oyster shell, and suspended by a silk thread passed 

 through the empty tube on the 21st of November. 



In three weeks, this group proved to be in fine condition. It con- 

 sisted of three large specimens of a beautiful orange colour, and of seven 

 smaller ones, dingy white. 



