276 ZOOPHYTES. 



upper by a flexible portion, which serves to protect 

 the upper part of the body when the whole is 

 expanded, at which time it is as large as the rest 

 of the cell; while, when the animal retracts, it is 

 folded up and drawn in after it, and completely 

 closes the mouth of the cell. The aperture of the 

 cell is formed by a lid, which folds down when the 

 polype is about to advance from it. These cells 

 appear under the microscope, like so many crystal 

 cups, and each one is the dwelling-place of a per- 

 fect animal, united to its neighbours in the cells 

 above and below him, by a common circulation. 

 Wondrous, indeed, is the structure of these po- 

 lypes ; their little tentacles, or arms, surrounding 

 the body like small bristles, are covered with innu- 

 merable minute cilia, or fringe-like hairs, all quickly 

 vibrating, and acting on the water like so many 

 paddles, producing all around them strong and 

 rapid currents. " Constantly," says Professor 

 Jones, " these streams of water pour along, some 

 rushing along the aspect of each tentacle towards 

 the mouth, and hurrying thither whatever food is 

 brought within their influence. Escape out of the 

 living whirlpool seems impossible, and every tiny 

 being that approaches its dread margin perishes. 

 Charybdis, with its fabled terrors, could not bear 

 comparison with the fierce vortex thus produced. 

 Soon as an animalcule comes within a given dis- 

 tance, it is whirled along directly to the mouth of 

 the gulph, where, if admissible as food, it enters 

 and is swallowed ; or, if rejected, it is dashed 

 away by other currents, running different ways, 

 and hurried to a distance. Neither does our admi- 

 ration cease after the food has passed the opening 

 of the mouth, for, in the throat itself, innumerable 



