Vorticellim.'] infusorial animalcules. 529 



divided, (P. 22, f. 8), and the nucleus. In others, lastly, all dis- 

 tinction of organs was lost ; the nucleus being the last to disappear. 

 (P. 22, f. 9.) 



The process whereby Vorticella so retract themselves within their 

 case, and become totally included within it. Stein calls the encysting- 

 process. With this phenomenon before him, and the obliteration of 

 organs witnessed, coupled with the fact of finding empty, rent cysts, 

 Dr. Stein was led to believe, that, by the breaking up of special 

 organs, and particularly by the peculiar agency of the nucleus, a 

 granular germ-mass was developed, the several portions of which 

 resolved themselves into spores, which subsequently escaped through 

 a hole in the enclosing integument, and formed a granular sub-stratum 

 similar to that to wliich he saw the rudimentary Vorticellai adhering. 

 (P. 22, f. 6, d.) and from which the elements of new forms seemed 

 to bo produced, these new forms finally passing tlu'ough certain 

 phases of development until they attained the characters of perfect 

 VorticcUo}. (See p. 522.) 



His subsequent researches, however, compelled Stein to set aside 

 this hypothesis, for he found that Vorticellce, like Vflffinicola and 

 Epidi/lis, after the encysted stage were transformed into Acineta-like 

 individuals, and then assumed the figure of Po</o/;7i/'yrt,/?.r«. Under 

 this last guise an apparent, marvellous act of conjugation took place 

 between two individuals ; the coalesced beings continuing to be sup- 

 ported on their two pedicles. Beyond this point this curious history 

 of the transformation of Vorticella has not been pushed. "We n:ay, 

 however, refer the reader to the account of the metamorphoses of 

 Einstylis by Dr. Stein, and would especially direct his attention to 

 the previouslj- published observations of M. Pineau, (see Part I., 

 page 52) on the transitions of Vorticella into Oxytricha. 



VoETicELLiNA nehulifera (V. nehiUfera et convallaria, M.) — The body 

 has the form of a bell fca)iipanulatej ; the expanded part, answering to 

 the mouth of the bell, being fi-inged with cilia ; the pedicle or stalk, 

 which is about five times the length of the body, is attached to the 

 convex apex, which is rather conical, when the creatiu-e is in health 

 but hemispherical when otherwise. The mouth is situated near the 

 margin, where the wreath of cilia is interrupted. These creatures 

 usually congregate together, though each is independent of its neigh- 



