162 THE ORGANIZATION 



sides in a thick layer of muscular substance which envelops the 

 whole body. At the tip of the bell the muscle has the form of a 

 conical bundle of fibres (ms) which, at the narrower end, is at- 

 tached to the top of the stem (p), and at the other to the bottom 

 (s) of the digestive cavity. The bell appears at the first glance 

 to have scarcely any obliquity of form, but that is because its edge 

 (d) is so prominent a feature with its thick folds and triple row of 

 numerous vibratile cilia, that it hides, as it were, the true charac- 

 ter of the disc which it surrounds. The position of its broad 

 throat will, however, fully vindicate its claim to a relationship 

 with the spiral type of conformation. The mouth (m) opens 

 close to the edge, and leads directly into the funnel-shaped throat, 

 or oesophagus (g). The latter plunges obliquely toward the left 

 side of the body, and at the same time downwards and inwardly 

 with a gentle spiral turn, and then diving still deeper it coils 

 around to its right (g" 1 ), and thins out almost to a point near the 

 bottom of the digestive cavity. The food is passed down this in- 

 clined funnel into the digestive cavity by the aid of vibratile cilia 

 which line it from mouth to bottom. What is the proper use of 

 this single long vibrating lash (/), which projects outwardly from 

 so great a depth, I cannot say precisely ; but it appears to be very 

 active in repelling certain particles of unwelcome matter, appar- 

 ently not palatable to the animal. That the digestive cavity is 

 one vast hollow, would seem to be proved by the fact, that, as I 

 have frequently seen, the whole mass of food which pervades it 

 everywhere, from the edge of the bell to the top of the conical 

 muscle, (ms,) revolves like a great transparent ball of compact 

 jelly and coarse, imbedded granules, one side of which passes 

 up on the right and then down on the left with a slow and meas- 

 ured turn ; and with such a uniformity of motion that any single 

 granule may be selected and watched throughout a whole revo- 

 lution, without the least doubt as to its course in the body. You 



/>, the stem ; d, the flat spiral of vibratory cilia at the edge of the disc ; ms, the 

 muscle ; m to s, the depth of the digestive cavity ; m, the mouth ; g, g l , the throat ; 

 J, the single vibratory lash which projects from the depths of the throat; cv, the 

 contractile vesicle ; n, the reproductive organ. Original. 



", p 3 I *, 



