CYLINDRA. 179 



Sub-gen. ziba, H. and A. Adams. 



Spire acuminate, wborls smooth, subnodose or keeled ; inner 



lip with the callus defined ; outer lip sometimes thickened in the 

 middle. 



apicata, Reeve. peculiaris. Reeve. 



carinata, Sivains. ' Senegalensis, Reeve. 



micans, Reeve. typha, Reeve. 



Genus CYLINDRA, Schumacher. 



Shell oliviform, subcylindrical; spire elevated, conical; 

 aperture linear; columella straight, with several oblique 

 plaits anteriorly ; outer lip thickened, crenulated. 



IJa^. C. nucea, Meuschen, pi. 19, fig. 5. Shell, C. cre- 

 nulata, Lamarck, fig. 5, a. 



There is no operculum on the foot of the animal, 

 which in every essential resembles that of Mitra : the 

 species are principally found crawling on sandy patches 

 among coral reefs, inside the barrier. 



Species of Cylindra. 



crenulata, Lain. ornata, Schub. 



dactylus, Linn. punctata, Sivains. 



fenestrata, Lam. Sinensis, Reeve. 



glans, Reeve. undulosa. Reeve. 



nucea, Meiisch. vultuosa, Reeve. 

 obesa, Reeve. 



