86 GENERA OF SHELLS. 



PURPURIFERA. 



Shell with a short canal ascending posteriorly, or an ohliquc 

 notch or demi-canal at the base of the aperture, directed to- 

 wards the back. 



Div. I. — Canal AoCending or curved towards 



THE back. 



Cassidaria. Shell obovate, or ovate ob- 

 long. Aperture longitudinal, narrow, termin- 

 ating at base, in a curved, subascending canal. 

 Lip varicose or reflected ; pillar lip covering 

 the columella, often rough, granular, tubercu- 

 lous or wrinkled. 



Distinguished from cassis by being, in general, less 

 inflated, but chiefly by its short canal, not being ab- 

 rupdy turned towards the back of the shell and being 

 but slightly curved or ascending. The spire is short, 

 without continuous varices : the columella is generally 

 loaded with small, oblong, wrinkled tubercles lying in 

 a ti-ansverse direction. 



(a.) Spire having varices. 



C. echinophora, ihyrrena, cingulata, striata, oniscus, 

 cancellata, carinata, flammea, fasciata, glauca, crumena, 

 plicaria, areola, zebra, decussata, abbreviala. 

 (b.) Spire without varices. 



C. rufa, pennata, testiculus, achatina, pyrum, zeylanica, 

 sulcosa, granulosa, saburon, canaliculata, semigranosa, vibex, 

 erinaceus, harpseformis. 



Cassis. Shell inflated. Aperture longi- 

 tudinal, narrow, terminated at base by a short 

 canal, turning abrupt backwards. Columella 



