174 OLlVlDiE, 



Cyprsea. The dorsal aspect is much like Cyprsea. M. sarda, 

 Kiener (Iv, 63). 



VOLVARIA, Lam. (Hyalina, Schum.) Shell subcylindrical, 

 spire very short or concealed ; outer lip of aperture without 

 varix or thickening. M. avena, Gmel. (Iv, 64). M. bulloides, 

 Lam. (Iv, 65). 



Family OLIYID^. 



Animal with a recurved siphon and voluminous foot, its lobes 

 usually reflexed over the sides of the shell, and fissured on each 

 side in front. Dentition (x, 15). 



Operculum corneous, small ; frequently wanting. 



Shell brilliantly colored, porcellanous, without epidermis, the 

 columellar lip, sutures and spire more or less covered with a 

 callous deposit ; outer lip simple, notched below. 



Subfamily OLIVINE. 



Head and tentacles more or less concealed ; mantle with a 

 tapering lobe in front, and a posterior appendage which reposes 

 in the channeled suture. 



Operculum present in Olivella, absent in the typical Oliva. 



Shell solid, smooth, subcylindrical, sutures channeled, inner 

 lip more or less plicate anteriorly. 



Olivella, Swainson. 



Rice-shell. Syn. — Olivina, d'Orb. Micana, Gray. 



Distr. — 31 sp. N. Carolina, W. Indies, W. Coast of America, 

 Senegal, China, Philippines, Australia, Polynesia. 0. undatella, 

 Lam. (Ivi, 66). 



Shell polished, small; spire produced, acute, suture canalicu- 

 lated ; aperture narrow behind, enlarged anteriorly; columella 

 plicated in front, callous posteriorly. 



Animal without tentacles or eyes, mantle with a large frontal 

 lobe; foot not very voluminous, truncate behind, the shield 

 narrow, the side-lobes small and acute. 



Operculum horny, thin, half ovate, with apical nucleus. 



Olivella is distinguished from Oliva by the small size of its 

 shell, its more produced spire, the presence of a large, thin, 

 horny operculum, and the want of eyes. D'Orbigny has observed' 

 0. Tehuelcha suddenly expand the lobes of its foot, and using 

 them to beat the water like the wings of the pteropods, dart 

 rapidly through the element. 



Oliva, Brug. 

 Syn. — Dactylidia, H. and A. Ad. Ispidula, Gray. Porphyria, 

 Bolten. Strephona, Browne. Dactylus, Klein. Galeola and Car- 

 mione, Graj^ 



