GASTEHOPODA. 227 



marked shells ; living in shallow water, on sandy flats, or 



congregating about stones. (Adams.) 



Fossil) 8 species. Tertiary. (The British species are pisanice.) 

 Sub-genuSi ColumbelUna^ B'Orbigny. 4 species. Cretaceous. 



France, India. 



Oliva, Lam. Olive, rice-shell. 



Type, 0. porphyria. PL YI., Fig. 16. 

 Synonym^ Strephona, Brown. 



Shell cylindrical, polished; spire very short, suture channelled; 

 aper'ure long, narrow, notched in front; columella callous, 

 striated obliquely; body-whorl furrowed near the base. No 

 operculum in the typical species. 



Animal with a very large foot, in which the shell is half 

 immersed; mantle lobes large, meeting over the back of the 

 shell, and giving off filaments which lie in the suture and furrow. 

 The eyes are placed near the tips of the tentacles. 



The ohves are very active animals, and can turn over, when 

 laid on their back ; near low water they may be seen gliding 

 about or burying in the sands as the tide retires ; they may be 

 taken with animal baits attached to lines. They range down- 

 wards to 25 fathoms. 



Distribution, 120 species. Sub-tropical, "West and East 

 America. West Africa, India, China, Pacific. 



Fossil, 20 species. Eocene — . Britain, Prance, &c. 

 Sub-genera. Olivella, Sw. 0. jaspidea, PL YL, Pig. 19. 

 Animal with small, acute frontal lobes. Operculum 

 nucleus sub-apical. 

 Scaphula, Sw. = OlivanciLlaria, D'Orbigny, PL YI., 

 Pig. 18, 

 Frontal lobes large, rounded, operculate. 



Agaronia, Gray. 0. hiatula, PL YL, Pig. 17. 

 No eyes or tentacles. Frontal lobes moderate, acute. 



Ancillaria, Lam. 



Etymology, ancilla, a maiden. 



Types, A. subulata, PL YL, Fig. 20. A. glabrata, PL YL, 

 Fig. 21. 



Shell like oliva; spire produced, and entirely covered with 

 shining enamel. Operculum minute, thin, pointed. Lingual 

 teeth pectinated. Uncini simple, hooked. 



Animal like oliva ; said to use its mantle-lobes for swimming. 

 (lyOrbigny.) In A. glabrata, a space resembling an umbilicus, 

 is left between the callous inner lip and the body-whorl. 



