GASTEROPODA. Qo 
marked shells; living in shallow water, on sandy flats, or 
congregating about stones. (Adams.) 
Fossil, 8 species. Tertiary. (The British species are pisanic.) 
Sub-genus, Columbellina, D’Orbigny. 4 species. Cretaceous. 
France, India. 
Oxiva, Lam. Olive, rice-shell. 
Type, O. porphyria. Pl. VI., Fig. 16. 
Synonym, Strephona, Brown. 
Shell cylindrical, polished; spire very short, suture channelled ; 
aperture 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 olives 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 Hast 
America. West Africa, India, China, Pacific. 
Fossil, 20 species. Hocene—. Britain, France, &c. 
Sub-genera. Olivella, Sw. O. jaspidea, Pl. VI., Fig. 19. 
Animal with small, acute frontal lobes. Operculum 
nucleus sub-apical. 
Scaphula, Sw. = Olivancillaria, D’Orbigny, Pl. VI., 
Fig. 18, 
Frontal lobes large, rounded, operculate. 
Agaronia, Gray. O. hiatula, Pl. VL., Fig. 17. 
No eyes or tentacles. Frontal lobes moderate, acute. 
ANCILLARIA, Lam. 
Etymology, ancilla, a maiden. 
Types, A. subulata, Pl. VI., Fig. 20. A. glabrata, Pl. VI., 
Fig. 21. 
Shell like oliva; spire produced, and entirely covered with 
shining enamel. Operculum minute, thin, pointed. Lingual. 
teeth pectinated. Uncini simple, hooked. 
Animat tike oliva; said to use its mantle-lobes for swimming. 
(D’Orbigny.) In A. glabrata, a space resembling an umbilicus, 
is left between the callous inner lip and the body-whorl. 
