GASTEROPODA. 259 



oxh-emely elongated, slender. Inhabits lakes and rivers 

 throughout the warmer parts of the world, retiring deep into the 

 mud in the dry season, and capable of suryiving a drought, or 

 removal from the water for many years. In the lake Mareotis, 

 and at the mouth of the Indus, ampullarise are abundant, mixed 

 w th marine shells. Their eggs are large, enclosed in capsules. 



Fig. 110. Ampullaria globosa. (Wilton.) 



and aggregated in globular masses. The dentition of ^. glohosa 

 is shown in Fig. 110. 



Distribution, 136 species. South America, West Indies, Africa, 

 India. 



Suh-genera. Pomus, Humph. A. ampullacea. Operculum 

 horny. 



Marisa, Gray (ceratodes, Guilding). A. cornu-arietes (PL IX., 

 Fig. 31). Operculum horny. Shell discoidal. 



Asolene, D'Orbigny. A. platse. Animal without a respiratory 

 siphon ; operculum shelly. Distrihution, South xVmerica. 



Lanistes, Montf. A. bolteniana, L. (PL IX., Fig. 32). Shell 

 reversed, umbilicated, peristome thin ; operculum horny. Dis- 

 tribution, West Africa, Zanzibar, Nile. 



Meladomus, Sw. Paludina olivacea, Sby. Shell reversed, 

 imperforate ; peristone thin ; operculum horny. 



? Amphibola, Schumacher. 



Synonyms, AmpuUacera, Quoy. Thallicera, Sw. 



Type, A. australis (PL IX., Fig. 33). 



Shell globular, with an uneven, battered surface ; columella 

 fissured ; outer lip channeled near the suture ; operculum horny, 

 sub-spiral. Animal without tentacles ; eyes placed on round 

 lobes ; air-breathing ; respiratory cavity closed, except a small 

 valvular opening on the right side ; a large gland occupies the 

 position of the gill of paludina; sexes united. (Quoy.) Mr. 

 Gray places this genus amongst the true pulmonifera. 



Distribution, 3 species. Shores of New Zealand and the Pacific 

 Islands. The living shells sometimes have serpulce attached to 

 them. (Cuming.) They are eaten by the New Zealanders. 



