462 Dr. R. Greef on the Structure and 



XLI.X. — Investigations upon the Structure and Natural History 

 oftJie Vorticellse. By Dr. Richaed Geeef. 



[Concluded from p. 397.] 



The Contractile Reservoir of the Vorticellse. 



In many Vorticellse, especially in Epistylis Jlavicans, Car- 

 chesium polypinumj &c., I have been able to observe the rosette- 

 like canal-system ascribed by Stein* to many other Infusoria; 

 but, as a rule, I could only see it very distinctly when the con- 

 tractions were rendered slow by pressure &c. At the commence- 

 ment of the systole, just as Stein describes, bubble-like vesicles 

 make their appearance round about the margin of the reservoir ; 

 and these, as the central reservoir becomes smaller, acquire a 

 rosette-like grouping, in which, however, the individual vesicles 

 are not generally all of the same size, whilst during diastole they 

 coalesce again into a single vesicle. Sometimes I have thought 

 that I could observe a communication between the contractile 

 reservoir and the initial portion of the alimentary tube (vesti- 

 bulum), in the vicinity of which the former is always situated ; 

 but I could never attain to certainty upon this point. 



The contractile reservoir of the Vorticell^ is always situated 

 within the cortical layer of the body, pretty close to the ex- 

 ternal cuticula ; it has a definite position here, which remains 

 unaffected by the currents of the general contents of the body — 

 a further indication that the cortical layer forms a firm paren- 

 chyma, which takes no part in the current of rotation, as 

 otherwise the contractile vesicle, as also the other organs 

 already mentioned with respect to this point (nucleus, alimen- 

 tary tube, &c.), must also constantly change its position. 



In Carchesium polypinum there is a very peculiar organ, 

 which, so far as I know, has not yet been described, and 

 which may take its place here provisionally, because it always 

 adheres to the contractile reservoir. It is, like the latter, a 

 vesicular but not contractile space, covered throughout its 

 whole periphery with fine, short, straight bacilli, which, ap- 

 parently, lie in a tangential direction to the surface (PI. XIV. 

 fig. 9, r) . The bacilli, however, can be observed only in the 

 fresh state, i. e. in the living animal ; when the Vorticellan 

 is dead, or too strongly compressed, they become indistinct, or 

 entirely disappear ; sometimes also I have missed them even in 

 uninjured individuals, whilst the organ under notice is itself 

 never wanting. Its inner space seems to contain a hyaline 

 fluid, which, however, does not always entirely fill it, so that 

 indentations and processes are often produced on its surface. 



* Der Organismus der Infusionsthiere, i. p. 88. 



