210 



NATICIDiE. 



Species of Ruma. 



Bahiensis, Itecluz. 



bicincta, TLecluz. 



bifasciata, Gray. 



fibrosa, Soul. 



litterata, Soul. 



macrotrema, Adams and Reeve. 



mamillaris, Born. 



maura, Lain. 



melanastomoides, Quoy. 



opaca, Uecluz. 



perspectiva, Uecluz. 

 Priamus, Recluz. 

 putamen, Meusch. 

 Samarensis, Recluz. 

 Sebse, Soul. 

 Senegalensis, Recluz. 

 sinnifB, Cliem. 

 sinnioidea, Recluz. 

 Zanzebarica, Recluz. 



Genus mamma, Klein. 



Animal entirely retractile within the shell. 



Operculum large, horny, simple. 



Shell ovate or subovate, solid, smooth, usually with- 

 out epidermis; spire small, acute, whorls simple ; aperture 

 semicircular; inner lip oblique, thickened, callous; umbi- 

 licus funiculate; columella adherent to, and spirally con- 

 torted in, the umbilicus, the apex more or less dilated, 

 convex and rounded. 



Syn. Uber, Humph. Albula, Bolt. Polinices, Monif. 

 Mamilla, Gray, not Schnm. Eucaryum, Ehrenh. Mamil- 

 laria, Swains. Naticina, Guild. 



Ex. M. mamilla, LimKBUs, pi. 22, fig. 6. Operculum, 

 M. Cumingii, Recluz, fig. 6, a, 6, b. Shell, M. mamilla, 

 fig. 6, c. 



The animals of this peculiar type of Naticidce inhabit 

 clear sand and muddy sand-flats, and may be readily 

 taken at low-water by following the marks they leave, 

 when they are usually discovered concealed under little 



