396 Dr. R. Greef on the Structure and 



cept by the existence of a curved canal starting from the apex 

 of the funnel. This is especially evident at the moment when 

 the elongated, pointed, and rapidly gliding morsel suddenly 

 stops, projects with a little knob from the narrow canal, and 

 then apparently falls immediately from it and into the body- 

 cavity. It is not to be imagined that the described phenomena 

 could be produced by the balls of coloured material being 

 pushed directly from the funnel without the intervention of 

 any canal into the nutritive jelly of the body-cavity, especially 

 as frequently one morsel after another traverses precisely the 

 same curve in the same compressed spindle-shape, the whole 

 course being often even beset with carmine particles arranged 

 in a row, so that they shine forth from the interior like a red 

 curved line. Thus the coloured particles often remain long 

 within the canal marking its course, whilst all around the 

 rotating movement of the nutritive jelly is maintained. It is 

 clear that, if these coloured particles had simply fallen from 

 the funnel into this nutritive jelly, they must have been carried 

 along by the current of the latter, especially the small carmine 

 granules, and that they could by no means have remained 

 continuously arranged one after the other in a curved line. 



When one has had the above-described pictures before one's 

 eyes, both in the way of direct observation and of carmine 

 feeding, one can hardly doubt that in reality a canal exists, 

 running from the apex of the funnel in a curve in the bottom 

 of the body-cavity and then opening freely into the latter. 



But we must not overlook the fact that, besides these 

 distinct and striking phenomena, others also come under ob- 

 servation, which, again, are of a kind to raise doubts as to the 

 existence of a special canal, and which, indeed, have led Lach- 

 mann and Stein to deny the presence of such a canal. Amongst 

 these there is, in the first place, the fact that the curves de- 

 scribed by the balls of carmine, i. e. the nutritive material 

 issuing from the funnel, are not always the same, but are 

 sometimes wider and sometimes narrower. This, however, in 

 my opinion, is to be explained in the following way: — The whole 

 alimentary tube, from the external buccal aperture situated 

 beliind the ciliated disk, to the funnel, has a definite form and 

 position not subject to change. It lies, as has already been 

 remarked, within the comparatively firm cortical layer enclo- 

 sing or forming the body-cavity, and is retained in its place by 

 this. But the fine curved tube issuing from the funnel is no 

 longer fastened hy the cortical layer ^ hut hangs free in the hody- 

 cavity^ and may therefore undergo a change of position now 

 and then by the movements of the nutritive jelly circulating 

 around it. Moreover it is easy to understand that the loosely 



