THE BELL ANIMALCULE. 19 



and one of the most curious of that restricted group of organisms 

 to which the term Infusoria is now applied. It is a little bell 

 of glassy transparency, with a broad and thick rim or lip, affixed 

 by a sort of nipple to a slender filament or stem, eight or ten 

 times its own length. The mouth of the bell is surrounded by 

 a fringe of cilia, which can be withdrawn at pleasure, but which, 

 when protruded, are kept in rapid play, producing a sort of 

 vortex in the water, by means of which minute particles of 

 alimentary matter are drawn into the mouth of the animal. 

 The long, slender, and flexible stems of these beautiful animals 

 are attached to the stalks or leaves of aquatic plants, where the 

 Vorticella} are frequently crowded together in such numbers as 

 to cover the parts with what looks to the naked eye like a deli- 

 cate white down. 



When not disturbed, the little Vorticella stretches out its 

 slender stern to the full extent, and turns gracefully about in the 

 water, keeping its cilia meanwhile in constant motion. But on 

 the least alarm, the cilia vanish, and the stem, with a rapidity 

 which the eye can scarcely follow, is contracted into a beautiful 

 spiral coil, so as to bring the bell close to the point of adhesion, 

 when it again gradually uncoils to its full length. It is hardly 

 possible to exaggerate the beauty of this spectacle, when a group 

 of the Vorticellse are viewed together by the aid of a powerful 

 microscope. At first the little creatures are seen floating loosely 

 through the water, most of them having their delicate stems 

 fully extended, or showing only slight undulations, and the bells 

 slowly roaming about, now turning the mouth, now the sides, 

 and now the foot, to the eye of the observer : suddenly, however, 

 and at the slightest tap, the entire throng start back, and before 

 the eye is well able to discover what has occurred, the glis- 

 tening bells may be seen closely nestling around the stalk of 

 the plant to which their stems are attached, gently swaying 

 from side to side, and beginning again to uncoil and stretch out 

 as before. 



The history and development of the young Vorticella are 

 fully as curious and interesting as the habits of the mature 

 animal. In all these microscropic beings the ordinary mode of 

 increase is by the parent animal separating into two or more 

 parts, each of which speedily attains to the dignity of a parent 

 itself. In the Vorticcllaj this process of self-division begins in a 



