OLIVELLA- 145 



cylindrical, with an angular ridge posteriorly; columella plicate 

 as far as the hind part. 



carneolus, Lam. tessellatus, Lam. 



crassus, Mart. volvarioides, Diiclos. 



pictus, Reeve. , 



Genus OLlVELLA, Swainson. 



Mantle with a large frontal lobe. Foot not very volu- 

 minous, truncate behind, shield narrow, side-lobes small, 

 acute. 



Operculum distinct, half-ovate, nucleus subapical. 



Shell oliviform ; spire produced, acute, suture canali- 

 culated ; aperture narrow behind, enlarged anteriorly ; 

 columella plicated in front, callous posteriorly. 



Si/n. Olivina, D'Orhiymj, not March. 



Ex. O. Tehuelchana, D'Orhigny, pi. 15, fig. 5. Oper- 

 culum, O. semistriata. Gray, fig. 5, a, 5, h. Shell, O. exi- 

 gua, Martini, fig. 5, c. 



The OlivellcB affect sandy localities, burying themselves 

 in the sand, but leaving no trace behind. M. D'Orbigny 

 observed O. Tehuelchana, while gliding rapidly along, 

 suddenly expand the lobes of the foot and shoot through 

 the water. 



Species of OliveUa. 



anazora, Duclos. fimbriata, Reeve. 



attenuata, Reeve. fulgida, Reeve. 



bullula, Reeve. falgurata, Adams and Reeve. 



cyanea, Reeve. gracilis, Brod. and Sow. 



dealbata. Reeve. Guildingii, Reeve. 



eburnea, Lam. hieroglyphica, Reeve. 



Esther, Duclos. inconspicua, C. B. Adams. 



exigua, Mart. lanceolata, Reeve. 



VOL. I. U 



