THE XEMATOCYSTS OF EOLIDS 
127 
touched upon by Cuenot. In what follows, Grosvenor's account 
is substantiated in all important respects. 
What happens during artificial digestion unquestionably occurs 
in the alimentary canal of an eolid. The tissues of the food ccelen- 
terate are aissolved and the nernatocysts remain in great quanti- 
ties free in the lumen of the tube. Alany of them are voided with 
the faeces, others find their way into the cnidophores. 
The passage from the digestive tract proper to the cnidophore 
is through the ciliated canal. Even were there no direct observa- 
Fig. 5 Transverse section through the base of a ceras showing within the lumen 
of the liver diverticulum, certain uninterpretable fragments; a considerable num- 
ber of undischarged nematocysts, and one crescentic diatom. 
tions such as those of Hancock and Embleton ('46), Trinchese 
('77-'81), and Grosvenor ('03), the occurrence of the same kinds 
in both cavities which the canal connects would suggest the deri- 
vation of the one group of nettles from the other. More sugges- 
tive still is the presence of ''foreign" bodies in the cnidophore, a 
fact noted by Hecht, by Hancock and Embleton, and by Grosve- 
nor. I have found uninterpretable fragments of tissue, bodies not 
tissue-like, and diatoms, in the liver diverticula and in the cnido- 
phores. The ciliated canal apparently has no power to distinguish 
