OF ANIMALCULES. 151 



f cresting subject, and enlarged our views of the operations 

 of Mature 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. For these researches w^e stand indebted to 

 the labours of Dr. Ehrenberg, from whose drawings 

 the figures are taken. One method of increase is pro- 

 bably from ova, but of this we have no direct evidence : 

 Dr. E. considers that the spawn is ejected, as with the 

 KoJpoda (159), 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 l-12000th of an inch in diameter, and 

 are clustered about the roots or stems of the old ones, as 

 shewn in figure 204 : they do not change their situation, 

 and are probably connected to the parent group by in- 

 visible filaments : they soon increase in size, when deli- 

 cate stems may be perceived, as may also a current in the 

 water towards the bell, indicating the presence of cilia. 

 At this stage of their growth, as shewn at figure 205, 

 they have been considered as a distinct species bySchrank, 

 under the title of V, monadica, because at this period the 

 stems do not contract spirally, as in the old ones. The 

 opinion that the young are produced from spawn adher- 

 ing to the stems, is favoured by the specimen drawn at 

 figure 211, which is a piriform variety, where a stem 

 will be seen attached to the parent. From some of the 

 specimens observed by Miiller, it is evident that they are 



