60 OLlVINyE. 



nucleus. Shell oliviform. pitlished ; spire produced, acute, sutui-e canal- 

 iculated ; aperture narrow behind, enlarged anteriorly ; columella plicated 

 in front, callous posteriorly. Dentition, PI. 12, fig. 14. 



Oliva, Brug. 



Tentacles enlarged at ihe base ; mantle with a posterior filament lodged 

 in the channeled suture of the spire ; foot long aud acuminate behind, 

 shield with the side-lobes tapering, acute, small. Operculum none. Shell 

 oblong, subcylindrical, polished ; spire short, conic ; suture canaliculated ; 

 aperture long and narrow, anteriorly widely notched ; columella obliquely 

 plicate, sulcate or striate in front, ijosteriorly callous; outer lip simple. 

 Dentition, PI. 2, fig. 12. 



Subgenus Lamprodoma, Swainson. 



Spire acuminate, elevated, suture canaliculated ; inner lip simple poste- 

 rioi'ly, but regularly numerously plicate anteriorly, the plicae more 

 transverse than in the typical group. 



Subgenus Callianax, H. and A. Adams. 



Shell swollen, ovate, with short conical spire and channeled sutures ; 

 aperture wide, elfuse in front ; inner lip with a very thick, defined callus, 

 and a few, frequently indistinct, anterior plaits. 



Subgenus Agauonia, Gray. 



Shell thin, oliviform, but a little effuse anteriorly ; spire acuminate, 

 suture channeled ; aperture rather wide, effuse anteriorly ; columella not 

 thickened posteriorly, tumid, with a few oblique plaits in front, Operculum 

 distinct. Tortoliva, Conrad ; T. Tex-ana, Conr. (PI. 3, fig. 30), is a synonym 

 of Agaronia. It is an eocene fossil from Texas. Dentition, PI. 2, fig. 13. 



Subgenus Olivancillaria, d'Orbigny. 



Head and tentacles concealed ; mantle with a large, thick, fieshy 

 appendage behind, partly covering the spire ; foot very voluminous, 

 truncate posteriorly, shield with the side-lobes very large and rounded. 

 Operculum present, small, half ovate, with subapical nucleus. 



Shell smooth, wide oblong, last whorl swollen ; spire very short, the 

 suture not canaliculated to the apex ; aperture rather large and \\ ide, 

 inner lip somewhat tortuous, with a large callosity behind, incurved in 

 the middle, and two or three oblique anterior plaits. 



The last three subgenera appear to connect the typical Olives with the 

 Ancillarise, in a regular series of stages of both animal and shell, as well 

 as in the presence of an operculum. 



Plochel^a, Gabb. 



Shell olive-shaped, suture nearly obsolete as in Ancillaria ; aperture 

 linear, deeply and obliquely notched at the base, as in Dibaphus ; outer 

 \i\} thickened internally in the middle ; inner lip callous and having 

 several transverse folds, of which the upper are the smallest ; columella 

 strongly recurved at the base. P. crassilabra, Gabb. PI. 3, fig. 22, 

 Tertiary, W. Indies. 



