GASTROPODA PROSOBRANCIIIATA. 47 



divided above, and outer lip thin. Tr. varlux L., Adriatic and Mediter- 

 ranean. 



Fain. Neritidse (Neritacea). With thick, hemispherical shell and opcrculum. 

 l-.vs stalked, behind the two long tentacles. Proboscis slmrt. cift.'ii 

 Foot large, triangular. Heart perforated by rectum, with two auricles. 

 L. Shell thick, hemispherical, spiral lateral ; aperture semi-circular. N. 

 Reel.; -V. (.Veriti/t/i') Jtuclatilis L. ; Nuricella Lam.; JV. clliptica Lam., 

 Pacific Ocean. 



2. Ptenoglossa. Without siphon, aperture of shell entire, without 

 excavation or canal. Tongue armed with rows of numerous small 

 hooks and without the median plates. 



Fam. Janthinidbe. Junthina bicolor Menke, Mediterranean. 

 Fani. Solariidse. (Wentle-traps). Scalarla cunt inn nix Lam., 8e. pri'tinxn 

 Larn., East Indies. Solarium perspectiwm Phil., Mediterranean. 



3. Rhachiglossa. With long proboscis invaginable from the base. 

 Tongue long and narrow with at most three plates in each transverse 

 row, a toothed median plate and an intermediate plate on each side, 

 which are often reduced to mere hooks, and may be absent. All 

 possess a siphon and are predatory. 



Fain. Volutidae (Faltenschnecken). Valuta v,i<l iilntn Lam., Xew Zealand ; 

 V. i-/'x[j/'rf/lio. East Indies ; Cymbixin, cethiopicum L. 



Fam. Olividae. Olica iitriculm Lam., Indian Ocean; liar pa vcntricosa 

 Lam., New Guinea. 



Fam. Muricidae (Canaliferae). Murc.r- Itrandarls L., Mediterrarean. fusi/x 

 mi xt rails. Quoy Gaim. Columbclla mtn-<itoria L.. Atlantic. 



Fam. Buccinidae. Whelks. Buccinitm undntum L. ; Nassa reticulata L. 

 Mediterranean ; Purpura lapillus L., North Sea. 



4. Toxoglossa. Tongue with two rows of long hollow hooks, which 

 can be protruded from the mouth. All possess a siphon, and usually 

 prey on marine animals. 



Fam. Conidse (fig. 520) (Kegelschnecken). Corns litterahiy L., East Indies. 

 Fam. Terebridae (Schraubenschnecken). Terebra dimidiata Lam. 

 Fam. Pleurotomidse. Pleurotoma nodifera Lam. ; CaKcellaria Lam. ; C. cnn- 

 cellata, Lam. 



5. Tsenioglossa. In each transverse row of the elongated radula 

 there are usually seven plates. Two small jaws usually found at the 

 mouth entrance. 



Holostomatous are : 



Fam. Littorinidae, (Winkles). Littorinalittorea'L. 



Fain. Cyclostomidae. Kespire air like the Pulmonata by vessels of the mantle 

 cavity. Live in damp places on land. Cyclostonm i-lcgaiis Diap. 



Fam. Paludinidae, (Flusskiemenschnecken). Inhabit fresh water. Palndinu 

 vivipara L. ; P. Impura Lam. 



Fam. Vermetidae, (Wurmschnecken). Vrrinctus arenarius L. 



Fam. Cerithiidae. Cerlthium, licvc Quoy Gaim. 



