Natural History of the Vorticellse. 391 



tides of food fall directly in balls into the soft parenchyma of 

 the body. Stein* afterwards confirmed Lachmann's obser- 

 vations, and also on the whole adopted the designations chosen 

 by him for the different parts of the digestive apparatus, the 

 only alteration being that he includes the two parts distin- 

 guished as oesophagus and pharynx under the latter name, as 

 he cannot distinguish Lachmann's pharynx from the preceding 

 tube, called the oesophagus, by any, even functional separation. 

 Both authors agree that there is no further canaliform continu- 

 ation of the alimentary tube from the posteriorly pointed end 

 of the pharynx, but that the alimentary materials accumulate 

 m the latter, and afterwards sink into the parenchyma of the 

 body which divides in an arched form. 



I must, in the fi.rst place, express my entire concordance with 

 the observations of Stein and Lachmann as regards the ciliary 

 spiral and the vestibulum in Carchesmm polypinum and many 

 others, especially of the smaller species of Vorticellffi (see 

 PI. XIV. fig. 9, in which the course of the ciliary spiral and 

 its relation to the vestibulum &c. in CarcJiesium jyolypinwn 

 is shown) . But in the larger species of Ejnstylis there is so 

 far a deviation from this, that here the spiral is not confined 

 to a single turn, but describes several turns upon the ciliated 

 disk before sinking into the vestibulum ; to this, indeed, Lach- 

 mann has already called attention. A multiple circle of cilia 

 of this kind occurs, for example, in our Epistylis jlavicans. 

 In this Vorticellan, moreover, the digestive apparatus appears 

 with so distinct and in part peculiar an arrangement, that we 

 will once more adhere to it in the investigation of this question 

 also. In Epistylis jiavicans the anterior ciliated disk bears 

 four circles of cilia (Stein and Lachmann state three), which 

 apparently lie concentrically around one another. Easy as it 

 is in many species of Vorticellans [Carchesium polypinum^ 

 Epistylis pUcatilis andparasiticaj Zoothamniuvi alternans^ &c.) 

 to detect the spiral course and the final bending into the vesti- 

 bulum of the series of cilia, it is just as difficult in Epistylis 

 Jlavicans^ probably chiefly because in this the so-called " pe- 

 duncle " of the ciliary organ is deficient. The peristome seems 

 rather to come directly against the ciliated disk as a thin border 

 turned back when the bell is fully opened, without being sepa- 

 rated from the disk, as in most Vorticellan, by that deep furrow 

 from within which the " cap-like " ciliary organ rises. The 

 external aperture of the alimentary canal therefore, so far as I 

 have as yet been able to see, is situated not merely behind the 

 ciliated disk, but also, differently from the other Vorticellse, 



* Der Organismus der Iiifusioiisthiere, ii. pp. 84 et setjq. 



