Vorticellina.'] THE INFUSORIA. 263 



instantly retract, bending the stem into a number of coils ; 

 this operation is performed so quickly, that the eye cannot 

 detect it ; in a few seconds, the creature may be observed 

 slowly uncoiling the stem. These curious animalcules are 

 endowed with several methods of propagation, the observa- 

 tion of which has thrown much light upon this interesting 

 subject, and enlarged our views of the operations of 

 Nature in her minute productions : many creatures which 

 we formerly considered as belonging to distinct genera 

 are now ascertained to be the same in different conditions. 

 One method of increase is probably from ova ; but of 

 this we have no direct evidence. Dr. E. considers that 

 the spawn is ejected, as with the Kolpoda, and that it does 

 not proceed from buds, or germs from the roots; their 

 first appearance is like several little specks, rather darker 

 than the surrounding mass, and possessing a tremulous 

 motion ; they are then not more than the 1-1 2000th of an 

 inch in diameter, and are clustered about the roots or stems 

 of the old ones ; they do not change their situation, and are 

 probably connected to the parent group by invisible 

 filaments ; they soon increase in size, when delicate stems 

 may be perceived, as may also a current in the water towards 

 the bell, indicating the presence of cilii. At this stage of 

 their growth, they have been considered as a distinct 

 species by Schrank, under the title of V. monadica, be- 

 cause at this period the stems do not contract spirally, as 

 in the old ones. From some of the specimens observed 

 by Miiller, it is evident that they are also produced by 

 buds. 



" The next method of propagation is by a division of the 

 parent. When this is to be effected longitudinally, the 



