GASTEROPODA. 



BuGESiA, Paladillie, 1866. 



^Jiell resembling somewhat a very small Cerithium or micro- 

 scopic LitJiasia, but differing generically in having a wide, 

 compressed, not callous columella like that of Lacuna. 



Distribution, B. Bourguignati, In washings of the Eiver Lez, 

 Montpellier. 



Anculosa, Say, 1821. 



Synonyms, Leptoxis, Eafinesque ; Anculotus auctores. 

 Type, A. praemorsus. 



Shell oval ; aperture entire and rounded in front ; columella 

 callously thickened above. 

 Distribution, 31 species. North America. 



Melajstopsis, including Pirena, see p. 248, W. M., ii. 



Pamtly YIL — PAJDTJDrisriD^.* 



The genera contained in this family are — 



Paludesta, Ampullaeia (Pomws, Marisn, Asolene), Lajstistes, 

 Meladomtjs, Bithinia, with the following sub-genera of the 

 last : — 



Stenothyra {Nematura), Hydrobia, Syncera, Faludindla, Lit- 

 torinella, Amnicola, and 



MoiTESSiERiA, Bourguignat, 1863. 



Type, Paludina Simoniana, Charpentier. 



Shell somewhat similar to that of Acme; test pitted; de- 

 pressions octagonal, tetragonal, and rounded according to their 

 position; peristome externally thickened; no operculum has 

 been observed. 



Distribution, 1 species. Saline springs at Pouradade (Py- 

 renees). 



Fossil, 3 species. Alluvium of the river Garonne, at Toulouse. 



PoMATiOPSis, Tyron, 1865. 



Synonym, Chilocylus, Gill. 



Shell elongated ; margin of aperture slightly expanded ; oper- 

 culum corneous, subspiral, without an internal process. 



Animal like that of Hydrobia, but the foot is furnished with 

 lateral sinuses ; terrestrial or amphibious. 



Distribution, species. America. 



* See p. 257, &c. 



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