P. The foot. 

 f. .. filaments. 

 o. .. operculum. 



T. The trunk 

 p. .. foot. 



operculum. 



13. Trochus Icevis, List. 



h. The head. 

 ee. .. eyes. 

 tt. .. tentacula. 

 p. .. male organ. 



14. Purpura. 



h. The head. 

 ee. .. eyes. 

 tt. . . tentacula. 



15. Buccinum undatum, half the natural size, seen on the left side ; the 



trunk drawn in, and the male organ turned back, and hidden in the 

 branchial cavity. 



a. The male organ. e. The position of the heart, 



c. .. siphon. f. . . mucous plates placed to the 



dd. .. position of the branchiae. right of the branchiae. 



16. Buccinum undatum, with the trunk and male organ extended, 



a. The male organ. 



b. .. trunk. 



c. .. siphon. 



17. Natica 



h. The head. 

 ee. .. eyes. 



//. . . fleshy appendages at the 

 base of each tentacu- 

 lum. 



18. Natica 



Fossar, A dan. magnified. 



o 

 tt. 



The tentacula. 

 operculum. 



m. The mouth. 



fool, 



