138 CONCHOLOGY. 



right edge folded back ; columella covered by a wide, smooth cal- 

 losity, uniting posteriorly with the right edge. Inhabits all seas 

 except the Northern. Five living species. Seven fossil. 



Cassidaria echinophora. Cassidaria striata. 



C. Tyrrhena. C. oniscus. 



C. cingulata. 



2. Genus Cassis. PI. XII. 

 Animal. Spiral, with the foot (which is shorter than the shell) 

 rounded anteriorly; mantle provided, before the respiratory cavity, 

 with a long open canal, used as an organ of prehension ; head 

 furnished ; a single pair of blackish tentacula, having the eyes at 

 an inflation about half way from the base ; mouth armed with a 

 proboscis. 



Shell. Inflated, oval, subinvolute ; spire slightly projecting ; 

 aperture long, oval, sometimes very narrow, terminated anteriorly 

 by a very short canal, sloped, and flexed obliquely towards the 

 back ; columella covered by a large callosity, indented throughout 

 its length ; operculum horny. Found in the Indian, Mediterra- 

 nean, and Equatorial seas. Twenty-five living species. Eight 

 fossil. 



Cassis cornuta. Cassis crumena. 



C. flammea. C. zebra. 



C. rufa. C. sulcosa. 



C achatina. C. canaliculata. 



C. areola. C. semigranosa. 



C. abbreviata. C. Madagascariensis. 



C. saburon. C. glauca. 



C. Ceylonica. C. testiculus. 



C. erinaceus. C. plicaria. 



C. tuberosa. C. decussata. 



C. fascinata. C. granulosa. 



C. pennata. C. pyrum. 



C. vibex. 



3. Genus Ricinula, PI. XII. 

 Animal. As above. 



