RUMA. 209 



inner lip with a large, smooth callns covering part of the 

 body-whorl and concealing the umbilicus. 



Sf/?i. Globulus, Sow., not Schum. AmpuUaria, Flem., 

 not Lam. Euspira, Agass. Bulbus, Brown, not Humph. 

 Globularia, Swains. Deshayesia, Raul. Cernina, Grai/. 

 Anomphala, Jonas. 



Ex. A. fluctuata, Sowerhy, pi. 22, fig. 4. 



The only recent species known of this genus, which 

 has, however, several extinct representatives, is an in- 

 habitant of the Philippines, where it is found in con- 

 cealed situations in the slimy mud of shallow bays; the 

 animal is very bulky and unable entirely to retract itself 

 within the shell; the operculum, if present, is quite rudi- 

 mentary. 



Genus RUMA, Chemnitz. 



Animal retractile within the shell. 



Operculum cartilaginous, oblong, narrower than the 

 aperture. 



Shell ovate-acute, rather thin ; spire pointed, whorls 

 often zoned; aperture oblong; inner lip straight, narrow, 

 reflexed; columella usually black or fusco-purpurescent; 

 umbilicus nude, pervious, not funiculate. 



Syn. Mamma (part), Klein. Mamilla, Schum. Nati- 

 cella, Stvains. 



Ex. R. mamillaris. Born, pi. 22, fig. 5. Operculum, 

 R. mamillaris, fig. 5, a, 5, b. Shell, R. mamillaris, fig. 5, c. 



By means of its strong, well-developed, fleshy foot, the 

 animal of this genus readily ploughs up the yielding sand, 

 seeking for bivalves ; but when the tide rises, the side 

 lobes and hind part of the foot are expanded, and the 

 Ruma flaps along above the surface of the sand. 



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