APPENDIX D, 



xcv 



'^'-' "§ bet, 



i4 



'^'-.\ 



\ 



rnru ij 



'^«eii k 



(i« 



seen 



'^'.^- resemble 

 '" ^^^ often mi=J' 



fKATi 



ce or abse 



*^"^ only espiicji,. 



leems 



extremely 

 ■^•i by no distffic 



I'll 



Ciliated Infusoria. — Stein declares* that within the body 

 oi Actinophrys sol^ and also within that oi Podophrya fixa^ a 

 ciliated germ is often produced, which subsequently develops 

 into a Vorticella. Cienkowski believes that the Actinophryna 

 of Stein were really Acinetina, though he also declares he 

 has seen the development of ciliated embryos within the 

 latter, which however give rise, not to Voriicellce, but to 

 organisms similar to those from which they have arisen. 

 Stein would inake Acineiina a mere developmental phase in 

 the life-history of Vorticellina, whilst the observations of Cien- 

 kowski would tend to establish them as a distinct and 

 separate family. Mr. Carter's^ observations, again, are partly 

 in accord with those of Stein, since he says he has frequently 

 seen the passage of Vorticella into Acineta; though they are 





and AclimjihrjM^ 

 J developmental pk 



,-^rt T*.^ - 



-eover, savs 



3y Ehrenber^^ is re 



\r^ 



f 



t from onetoibj otherwise in agreement with those of Cienkowski, since he 



, there is an actual It;! ^^7^ ^^ ^^^ never seen the young oi Acineta assume any 



other form than that oi Acineta, 



4 



Stein believes that encysted Vorticellce, after undergoing 

 certain metamorphoses within their cyst-wall, may be con- 

 verted, according to the influence of external conditions, 

 either into an Actinophrys or into a Podophrya. The creatures 

 so produced are then thought to give birth to a ciliated 

 embryo, which is at first lodged within a definite cavity in 

 the substance of their body. The embryo is pear-shaped, 

 with a central constriction, and it is provided with one or 



jor 



emarks that, 



certain it*-- 



ble to determine** 



between 



I or as 



s extreme 



ihe same species 



taking p;;^:; 



and <if i^ 



lOl. 



fission 



, hour, aij -„f -|. 

 -n- format " ^„ e, 



but v^-b V K 

 the fr' Aible 



D 



^is'^'^.o^ 



the liberated segments. . , . Cilia could not be perceived over the 

 whole surface. . . . After waiting patiently for twenty minutes, I saw 

 the motion cease; and, at the same time, short tentacles made their 

 appearance, which were protruded more and more ; and in a few 

 niinutes afterwards the segment regained the spherical form: thus, 

 after moving about freely for a time, it was again transformed into 

 a Podophrya,' This was witnessed, Cienkowski tells us, by other 

 observers as well as himself, and the phenomena are in some respects 

 comparable with what takes place in the formation of the ciliated spore 

 of Vaiicheria. (See vol. i. p. 175.) 



' Die Infusionsthiere auf ihre Entwickelungsgeschichte/ Leipzig, 1854. 

 ^ 'Ann. of Nat. Hist.,' 1857, vol. xbc. p. 260. 



errup'' 



e(ily 



