POLYPES AND INFUSORIA. 387 



silently build up reefs and shoals, justly dreaded by the 

 navigator; and sometimes giving origin, as they rise 

 to the surface of the sea, to islands, which the lapse of 

 ages clothes with luxuriant verdure, and peoples with 

 appropriate inhabitants."* 



Most of the polypes are fixed and stationary ; but the 

 hydra and some others have the power of changing their 

 positions, which they do in search of the light of the 

 sun. They do not appear to have organs of sight re- 

 quiring light ; but still they delight in the solar influences. 

 The most extraordinary fact connected with the hydra 

 is its being multiplied by division. If an incision be 

 made in the side of a hydra, a young polype soon de- 

 velopes itself; and if one of these creatures be divided, 

 it quickly restores the lost portion of its structure. The 

 A T arieties of the polypes are exceedingly numerous, and 

 many of them are in the highest degree curious, and 

 often very beautiful. The actinia, like flowers, appear 

 to grow from the rocks, unfolding their tentacula to the 

 light ; and, in the excitement due to their eagerness for 

 prey, they exhibit a beautiful play of colours and most 

 interesting forms. Microscopic zoophytes of the most 

 curious shapes are found, all of which attest, under 

 examination, the perfection of all created things. 



Infusoria and animalcula, animals, many of them, 

 appearing under the microscope as little more than a 

 transparent jelly, must be recognized as the most 

 simple of the forms of life. They exist in all waters 

 in uncountable myriads ; and, minute creatures as 

 they are, it has been demonstrated that many of the 

 great limestone hills are composed entirely of their 

 remains. 



The acalephse, or the phosphorescent animals of the 

 ocean, are no less curious. From creatures of the most 



* General Outline of the Animal Kingdom : by Professor Thomas 

 Kymer Jones, F.Z.S. 



