162 



point ; the opening terminating in a notch ; the columella 

 smooth, with an acute base. Recent and fossil. PL iv. 

 fig. 15. 



41. Cassis. A ventricose univalve; the aperture long, 

 terminating in a short reflected groove ; the lips subden- 

 tated: the left lip flattened, and forming a ridge on the 

 body of the shell ; the columella plaited on its lower part. 

 Recent and fossil. PL iv. fig. 16. 



42. Nassa. An oval univalve ; the opening terminating 

 inferiorly by an oblique reflected notch ; a callosity on the 

 left side covers the columella, forms into a transverse fold 

 in the upper part, and has its base obliquely truncated. 

 Recent. PL iv. fig. 17. 



43. Purpura. An oval and sometimes tuberculated or 

 spinous univalve ; the opening terminating in a short oblique 

 groove, notched at the extremity. The columella naked, 

 flat in the whole of the lower part, and finishing at its base 

 in a point. Recent and fossiL PL iv. fig. 18. 



44. Strombus. A slightly ventricose univalve, termi- 

 nating inferiorly by a short truncated or notched groove ; the 

 right edge dilating with age into a wing or lobe, having a 

 sinus distinct from the notched canal at the base. Recent 

 and fossil. PL iv. fig. 19. 



45. Pterocera. A ventricose univalve, terminating in- 

 feriorly by an elongated canal ; the right edge dilating with 

 age into a digitated wing, with a sinus at its summit. 

 Recent. PL iv. fig. 20. 



46. Rostellaria. A subturriculated or fusiform univalve, 

 terminating at its base with a lengthened canal, with a sharp 

 beak ; the lip, dilating with age, is either whole or dentated, 

 with a groove at the lower end, and a sinus extending to the 

 summit of the spire. Recent and fossil. PL iv. fig. 21. 



47. Murex. An ovate or oblong univalve, with rough, 

 spinous, or fringed longitudinal sutures ; base channelled. 

 Recent and fossiL PL iv. fig. 22. 



