130 Mr. H.J. Carter on the Orf/anizafion of Infusoria. 



the bodv, and periplieral, while the vesicuhi is in the anterior 

 extremity. 



The apparent quiescent state of the vcsicula in Astasia, Eu' 

 qlnia, &e. may be an approaeh to its disappearance altogether 

 as a distinct orsjan, and therefore a step nearer to the vegetable 

 kingdom. But Schneider, in allusion to this, rpiotes a passage 

 from Cohn, in which the latter observes, that " internal pulsating 

 spaces" have been discovered in "certain genera of Algae;" on 

 which Schneider justly remarks, that if they "occur in the 

 swarm-cells of Conferrtp, they certainly cease to be a character- 

 istic of animal nature* ;" — thus rendering useless another di- 

 stinguishing ])()int between animals and plants at this part of the 

 organic kingdom, which after all, perhaps, may be foinid to have 

 its homologue in the vacuoles of the vegetable protoplasm. 



That the vcsicula is a distinct organ, and not merely a space 

 like the digestive globule, might be inferred from its always 

 occurring in the same place in the same species; but in addition 

 to this, the fact was on one occasion most satisfactorily demon- 

 strated to me by its remaining pendent in a globular form to the 

 buccal cavity of a Vorticclla, when, by the dccom])Osition of the 

 sarcodc, and evolution of a swarm of rapidly moving monadic 

 ])articles, these two organs, with the cylindrical nucleus or gland, 

 though still slightly adhering to each other, were so dissected 

 out as to be nearly sej)arate ; and thus yielding in position from 

 time to time, as they were struck by the little ])articlcs, their 

 forms and relative positions respectively became particularly 

 evident (fig. 70 a). 



Although globular in shape, yet, as beff)re stated, it is ac- 

 companied in Paramecium aurelia by a variable number of pyri- 

 form sinuses, which are arranged around it in a stellate form. 

 In most of the other animalcules these are globular, and, under 

 exhaustion of the animalcule from various causes, are frequently 

 go distended, and thus so approximated, as to assume the ap- 

 pearance of an areolar structin-e, immediately in contact with 

 the vcsicula (fig. HI). Each globular sinus, however, would ap- 

 pear to be the proximal or largest of a concatenation of smaller 

 ones, which diminish in size with their distance from the vcsicula 

 (fig. 82 d). The vcsicula becomes doubled preparatory to fissi- 

 paration, and therefore appears dual in Vorticella, and quadruple 

 in Parainecimn, fee. (fig. 09) ; and it is interesting to find tiiat 

 in the metamorphosis of the; former into Acineta it frequently 

 acquires a plurality similar to that which obtains in the llhizo- 

 poda generally f. 



* Loc. cit. p. ;330. 



t See particularly Stein's wnrk on the Development of Infusoria. 



