148 ANCILLINiE. 



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



Shell thin, not umbilicated ; spire elongated, suture ena- 

 melled ; inner lip with the callus moderate, defined ; outer lip 

 simple. 



bicolor, Gray. oblongus, Sow. 



elongatus, Oray. Tankervillianus, Sow. 



marginatus, Lam. 



Genus ANCILLA, Lamarck. 



Shell oblong, subcylindrical, polished ; spire short, su- 

 ture filled up with enamel ; aperture large, dilated, effuse 

 anteriorly ; columella callous anteriorly, twisted ; outer lip 

 thin, simple, acute. 



Syn. Olivula, Conrad. 



Ex. A. obtusa, Swainsoii, pi. 15, fig. 7. Operculum, 

 A. obtusa, fig. 7, a, 7, b. Shell, A. torosa, Meuschen, fig. 

 7,6-. 



The Ancill(B inhabit submerged sand-banks, and pro- 

 gress with a swift gliding motion ; sometimes they expand 

 the large lobes of their foot in a horizontal direction, and 

 swim or dart through the water. They chiefly inhabit the 

 shores of Africa, though a few have been found in the 

 Indian and Australian Seas. 



Species of Ancilla. 



albisulcata, Soic. effusa, Swains. 



ampla, Gmel. fulva, Swains. 



aperta, Sow. lineata, A. Adams. 



Caffra, Forsk. ventricosa. Lam. 

 castanca, Soiv. 



