Natural History of the Vorticellse. 397 



pendent tube may even be more or less curved, according to 

 the size of the morsel &c. It is also to be borne in mind that 

 under these circumstances mistakes may very easily occur, and 

 that we may fancy that we perceive a change of curve, whilst 

 it may be only that either by twistings of the animal itself or 

 by displacement of the tube the direction of the curve has 

 become diiferent, especially by the fact that at one time the 

 free end of the tube is turned to the side, and at another more 

 or less towards the observer. This also explains why, when 

 a Vorticellan is sufficiently compressed, the curves are usually 

 most regular, as by the mere compression of the body the 

 movements and changes of position of the tube are limited. 



Another objection against the existence of a distinct canal 

 is, that the morsel pushed in from the funnel does not always 

 traverse the same course, but escapes at a greater or less dis- 

 tance from its original point of issue. But this appearance 

 may also in many cases be produced by the above-mentioned 

 changes of position of the movable tube. On the other hand, 

 under certain circumstances, especially when the body-cavity 

 is for the most part emptied of its solid constituents and filled 

 with more or less fluid contents, and therefore with a diminished 

 pressure, the delicate tube appears to possess a great extensi- 

 bility, in consequence of which the morsels gliding through it 

 may then become balled together and widened earlier than 

 otherwise. This applies especially to water, which, when ac- 

 cumulated in the funnel and transferred into the curved tube, 

 dilates the latter by forming a large drop, which only disap- 

 pears gradually by mixture with the nutritive jelly. 



The above-cited observations, as already remarked, apply 

 especially to Epistylis flavicans. In the other Vorticellee I 

 have been unable to demonstrate the canal in question with 

 the same certainty, although in many others also I have been 

 able to ascertain by direct observation the fine linear continu- 

 ation of the apex of the funnel into the body-cavity. It is 

 possible, however, that in other Vorticellse this tube is shorter 

 than in Epistylis flavicans ^ or perhaps that it may occasionally 

 be entirely wanting — for example, immediately after fission ; 

 upon these points further observation may decide. Moreover 

 the Epistylis under notice also differs from the allied forms 

 inasmuch as in it the bellied, pyriform funnel always seems to 

 be distinctly marked off from the preceding oesophagus, and is 

 consequently to be regarded as a special part. In considera- 

 tion of this, we might perhaps see in this funnel the first 

 attempt at the formation of a stomach with proper walls, and 

 in the curved canal issuing from it a likewise very primitive 

 intestine. 



[To be continued.] 



