216 CASSIDID^. 



Operculum, S. glauca, Linn(Bus, fig. 2, a, 2, b. Shell, 

 S. sulcosa, Born, fig. 2, c. 



The oval form, irregular varices, and rather pointed 

 spire serve to characterize this genus; the nature of the 

 operculum at once distinguishes it from Cassis, and its 

 presence from Morum. 



Species of Semicassis. 



anceps, H. and A. Adams. recurvirostrum, Wood. 



canaliculata, Brug. Saburon, Adans. 



cicatricosa, Meusch. semigranosa, Layn. 



gibba, Gmel. sulcosa, Born. 



Japonica, Reeve. tessellata, Chem. 



pila, Eeeve. ventricosa, Mart. 



Sub-gen. phalium, Link (Bezoardica, Schum.). 



Shell transversely striated; spire acute, whorls angulated, 

 variced ; inner lip rugosely plicate ; outer lip strongly dentate 

 within. 



areola, Lijin. exarata, Reeve. 



bisulcata, Schub. and War/. glauca, Linn. 



coronulata, Sow. plicata, Linn. 



decussata, Linn. undata, Mart. 



Sub-gen. casmakia, H. and A. Adams (Cassidea, Sivainson, 



not Link). 



Shell smooth, whorls simple or subplicate; spire somewhat 

 elevated ; inner lip smooth ; outer lip usually simple or slightly 

 crenate internally. 



achatina, Lam. quadrata. Link. 



paucirugis, Mke. turgida, Reeve. 



pyrum, Lam. vibex, Linn. 



