§ 12. THE FOOD OF ZOOPHYTES. 607 



found depths of the ocean. The small parasitical species, 

 when dried, appear like spots of a chalky substance on the 

 sea-weed. The increase of the Flustra is thus described by 

 Lamouroux :* — "When the animal has acquired its full 

 growth, it flings from the opening of its cell a small globular 

 body, which fixes near the aperture, increases in size, and 

 soon assumes the form of a new cell ; it is yet closed, bu, 

 through the transparent membrane that covers its surface 

 the motions of the polype may be detected ; the habitation 

 at length bursts, and the tentacula protrude, eddies are 

 produced in the water, and conduct to the polype the atoms 

 necessary for its subsistence." 



12. The Food of Zoophytes. — However improbable it 

 may appear to the mind unaccustomed to investigations of 

 this nature, that beings so minute as those under examina- 

 tion should prey upon living forms yet more infinitesimal, 

 the fact is nevertheless unquestionable. It is even possible 

 to select the food of animalcules much smaller than the 

 polypes of the Flustra, and thus exhibit their internal struc- 

 ture. This experiment is easily shown under a good micro- 

 scope, and the animalcules termed Vorticellce, a very abun- 

 dant family of Infusoria, are best adapted for the purpose. 

 Immediately on a minute particle of a very attenuated 

 solution of pure carmine or indigo being applied to a drop 

 of water containing a group of the Vorticellce^ the most 

 beautiful phenomena are observable. Currents are excited 

 in the fluid in all directions, by the rapid motion of the 

 cilia which form a crown round the anterior part of the body 

 of the animalcules, and the particles of indigo are seen 



* " Corallina ;" an excellent abstract of Lamouroux's " Memoir on 

 the Flexible Corals " (one vol. 8vo. 1834), p. 43. 



f The Vorticellae are hyaline vasiform animalcules, attached by a 

 slender peduncle at the base, and having rows of cilia disposed in zones 

 round the margin : these, when seen in some directions while in rapid 

 motion, appear like wheels ; hence they are commonly called Wheel- 

 animals. See " Thoughts on Animalcules," PL III. 



