GASTEROPODA. 



Bugesia, Paladilhe, 18G6. 



Shell resembling somewhat a very small Cerithium or micro- 

 scopic Lithasia, 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, Kafinesque ; Anculotus auctores. 

 Type, A. prsemorsus. 



Shell oval ; aperture entire and rounded in front ; columella 

 callously thickened above. 

 Distribution, 31 species. North America. 



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



Family YIL— Paxtjdinid^.* 



The genera contained in this family are — 



Paxudina, Ampullahia (Pomus, Marisa, Jsolene), Lastistes, 

 Meladomus, Bithenta, with the folhnv jig sub-genera of the 

 last : — 



Stenothyra (Nematura), Hydrobia, Syncera, Paludinella, 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 Fouradade (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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