GASTEEOPODA. 



259 



extremely 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 surviving a drought, or 

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

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

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



rig. 110, AmpuUaria globosa. (Wilton.) 



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

 is shown in Eig. 110. 



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

 India. 



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

 horny. 



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

 Pig. 31). Operculum horny. Shell discoidal. 



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

 siphon ; operculum shelly. Distribution, South America. 



Lanistes, Montf. A. bolteniana, L. (PI. 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, Ampullacera, Quoy. Thallicera, Sw. 



Type, A. australis (PI. 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 serpulm attached to 

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



