THE GASTROPODA 



157 



over the shell (Fig. 70). Genera Cypraea, Linnaeus ; shell ventricose 

 with a crenelated colnmella. Pustularia, Swainson ; differs from Cypraea 

 in having an internal shell. Ovula, Bruguiere ; columella smooth, both 

 ends of the aperture canaliculated (Fig. 136). Pedicularia, Swainson; 

 attached to corals; foot small ; shell irregular with an expanded aperture. 

 Erato, Risso ; shell piriform, with a prominent spire. FAMILY 46. 

 TRITONIDAE, Adams. Shell turriculated and siphonated, thick, each 



FIG. 135. 



Female Janthina, with egg-float () attached to the foot. 6, egg-capsules ; c, ctenidium ; <>, 

 cephalic tentacles. (From Lankester, after Owen.) 



whorl of the spire provided with varices ; foot broad and truncated 

 anteriorly ; pallial siphon well developed ; a proboscis. Genera Triton, 

 Montfort ; varices not continuous from one whorl to another ; eyes at the 

 bases of the tentacles (Fig. 44, A). Persona, Montfort ; whorls irregular ; 

 eyes half-way up the tentacles. Ranella, Lamarck ; varices continuous 

 from one whorl to another. FAMILY 47. COLCMBELLIXIDAE, Fischer. An 

 exclusively fossil family ; shell with prominent spire, narrow aperture, and 

 callous columella. Genera Columbellina, d'Orbigny ; cretaceous. Colum- 

 bellaria, Rolle ; Jurassic. Zittelia, Gemellaro Jurassic. Peter sia, Gemellaro ; 

 Jurassic. FAMILY 48. CASSIDIDAE, Adams. Shell ventricose, with 

 elongated aperture and short spire ; foot broad and rounded anteriorly ; 

 proboscis and siphon long ; oper- 

 culum with marginal nucleus. 

 Genera Cassis, Lamarck ; shell 

 varicose, with narrow aperture. 

 Cassidaria, Lamarck ; shell with- 

 out varices, aperture oval and 

 canaliculated. Oniscia, Sowerby ; 

 shell oval, with a linear aperture. 

 FAMILY 49. OOCORYTHIDAE, 

 Fischer. Shell globular and Fl - 136 ' 



. -11 Oeula. animal and shell, right-side view. 1>, 



ventricose; aperture oval and cephalic tentacles ; d, foot ; h, mantle-skirt , which 



canaliculated ; opercillum spiral. is naturally carried in a reflected condition so as 

 i-,. , , , to cover in the sides of the shell. (From Lan- 



Genus (Jocorys, t ischer ; abyssal, kester, after Owen.) 

 FAMILY 50. DOLIIDAE, Adams. 



Shell ventricose, with short spire and wide aperture ; no varices and 

 no operculum ; foot very broad with projecting anterior angles ; siphon 

 long. Genera Dolium, Lamarck ; shell with a short canal ; ocular 

 tubercles distinct from the tentacles ; mantle not reflected over the 

 shell. Pijrula, Lamarck ; canal long ; spire very short ; mantle reflected 

 over the shell; eyes sessile (Fig. 71). FAMILY 51. SOLARIIDAE, 



