M.'NiLieberkuhn on the Anatomy of the Infusoria, 329 



found the Bursaria just named during spring and summer in 

 standing water near Tempelhof ; it agrees in the main with 

 Ehrenberg^s Bursaria Vorticella. The buccal orifice is situated as 

 ill Bui^saria truncatellaf in which however I did n ot observe any 

 contractile vesicle at the posterior end of the body. The speci- 

 mens of B. truncatella I observed were all about ^rd of a line or 

 more long, those of B. Vorticella at most ^th of a line. The 

 latter is in any case not a Leucophrys ] therefore, in case Ehren- 

 berg considers his Bursaria Vorticella a Leucophrys, it is a dif- 

 ferent animalcule from the latter. I was equally unable to 

 satisfy myself of the correctness of Schmidt's view in the Para- 

 mecia. When a specimen of Paramecium Aurelia lies so that 

 the contractile vesicle, either the anterior or posterior, is seen at 

 the margin, it appears, under certain circumstances, as though 

 a short canal ran directly out through the integument of the 

 animalcule ; but in reality it only runs into the integument, and 

 turns round toward the side of the body directed away from 

 the eye. I found the same in Paramecium Chrysalis also ; it was 

 always one of the rays of the contractile vesicle which presented 

 to Schmidt the appearance of an external orifice. The same is 

 the case in Bursaria flava, where I could always trace the cur- 

 vature of the vessel toward the opposite side of the body most 

 distinctly. F. Stein strongly questions the external opening of 

 the contractile vesicle in the VorticellcB. Hence it is clear, that 

 the explanation of the contractile vesicles as part of a water- 

 vascular system is unproven. 



Is it however established, on the other hand, that the con- 

 tractile reservoirs pour back their contents again into the paren- 

 chyma whence they receive it, as Von Siebold says ? And if this 

 is the case, how does it happen ? Everything indicates most 

 strongly that the contractile vesicles are filled out of the vessels 

 during the diastole. We see how, during this process, the 

 swollen part of the vessels near their embouchure gradually Or 

 suddenly return to their smallest diameter, as the stellate figure 

 vanishes. And I have observed a part of a vessel inflated with 

 the fluid, originating at the extreme end of the animalcule, 

 traverse the whole distance up to the contractile vesicle during 

 a single diastole. This phsenomenon may be supposed to show 

 that the absorbed fluid which had inflated the vessel into a 

 globule, flowed during the said period into the contractile 

 reservoir. ,)ho[ \o ^&o;)iir,J^fJjjg bs'xuovob to Bair,m'ii 



But if there is a fair presumption thai the coiitractile' vesicles 

 are filled out of the vessels, the above observations teach us 

 nothing whatever on the question as to where the fluid flows 

 during the systole. 



I have hitherto only become acquainted with one fact relating 



