224 



MAirUAL OF THE MOLLTJSCA. 



channelled behind ; operculum suhsjpiral (quoyia) or semi-OYate. 

 PL YI., Fig. 7. 



Distribution, 27 species. West Indies, Eed Sea, Bourbon, 

 India, Pacific, and Peru. 



Fossil, Miocene ? 



Small coast shells, resembling periwinkles, with which 

 Lamarck placed them. This genus is now generally placed 

 among the Littorinidse. 



Magiltjs, Montfort, 1810. 



Synonyms, Campulote, Gruettard, 1759. Leptoconchus, Biippell. 



Type, M. antiquus. PL Y., Pigs. 19, 20. 



Shell, when young, spiral, thin ; aperture channelled in front ; 

 adult, prolonged into an irregular tube, solid behind; operculum 

 lamellar. 



Distribution, 4 species. Eed Sea, Mauritius. 



The magili live fixed amongst corals, and grow upwards with 

 the growth of the zoophytes in which they become immersed ; 

 they fill the cavity of the tube with solid shell as they advance. 



Cassis, Lam. Helmet-shell. 



Synonyms, Bezoardica, Schum. Levenia, Gray. Cyprsecassis, 

 Stutch. 



Type, C. flammea. PL YL, Pig. 14. 

 Shell ventricose, with irregular varices ; spire 

 short ; aperture long, outer lip reflected, denticu- 

 lated ; inner lip spread over the body-whorl ; 

 canal sharply recurved. Operculum small, elon- 

 gated; nucleus in the middle of the straight 

 inner edge (Fig. 84). Lingual teeth 3, 1, 3, as 

 in Fig. 85. 



The spiny buccal plates of Cassis have been 

 mistaken by Gray and Adams for the teeth, which 

 in this genus, and also in Triton, are very minute 

 and transparent. 



Fig. 84 

 of Cassis. 



Operc. 



Fig. 85. Cassis sdburon. (Original). 



Distribution, 37 species. Tropical seas; in shallow water. 

 "West Indies, Mediterranean, Africa, China, Japan, Australia, 

 New Zealand, Pacific, Mexico. 



