330 VEEMETID^E. 



coast, off Budleigh Salterton, six miles from the shore, in ten 

 fathoms water. 



To describe the organs of this animal would be a repe- 

 tition of what has been said on Caecum trachea ; I will only 

 recapitulate them and notice the modifications thereof. 



The brown ovarium, light green liver, and the rectum with 

 its contents of pale brown pellets, extending from the py- 

 lorus to the doubling amongst the folds of the liver, were 

 distinctly visible through the transparency of the shell. The 

 stomach, body and neck were of the purest white ; the lines 

 forming the canal or groove in the neck are less developed 

 than in the former species ; the buccal mass is of the palest 

 blush colour, and the corneous plates of the most delicate 

 and lightest green. The spiny tongue was not seen ; the same 

 default occurred in Caecum trachea, probably from its white 

 colour and extreme slenderness; it doubtless exists. The 

 mantle is thick, circular and muscular, closely fitting the 

 shell ; the eyes are fixed precisely as in C. trachea the very 

 minute branchial leaflet is of the palest rose-colour, but the 

 mantle must be removed to see it, owing to its extreme tenuity. 



I now come to those organs in which there are some 

 variations. The tentacula, as in its congener, are frosted- white 

 and setose, but they appear to be proportioiiably longer, 

 slenderer, and more clavate at the tips ; these variations how- 

 ever are scarcely appreciable. The foot is very short, trun- 

 cate in front, rounded behind, and carried much more laterally 

 in this species than in C. trachea ; and on its posterior upper 

 part is the most differential point in the animals, the curious 

 operculum, which is circular, and has six or seven spiral 

 turns, of a pale yellow ; but instead of being concave or flat 

 without, as in C. trachea, it is the reverse. Supposing the 

 flat, spiral, circular operculum of the last species, pushed 

 out from its inner surface, or inverted, and thus forming 

 a cone of six or seven minute narrow terraces, one above 

 the other, we then obtain some idea of the form of that in 

 Caecum glabrum. 



This creature marches, and in its course performs exactly 

 the same manreuvres, as the larger species. I thought the 



