GASTEEOPODA. 267 



its inner side, and slightly so externally ; operculum shelly, 

 multi-spiral. 



Distribution^ 6 species. West Indies — China. Low water to 

 GO fathoms. 



Fossil, 5 species. Tertiary — . Britain. 



EuoMPHALrs, Sowerby. 



Etymology, eu, wide, and omphalos, umbilicus. 



Synonyms, Schizostoma, Bronn. Straparollus, D'Orbigny. 

 Oiihileta, Yanuxem. Platyschisma, M'Coy. 



Type, E. pentagonalis. PI. X., Fig. 18. 



Shell depressed or discoidal ; whorls angular or coronated ; 

 aperture polygonal ; umbilicus very large ; operculum shelly, 

 round, multi-spii-al. (Salter.) 



Fossil, 80 species, L. silurian— Trias. North America, Europe, 

 Australia. 



Siib-genus. Fhanerotinus, J. Sby. 1840, E. cristatus, Phil. 

 Carb. limestone. Britain. 



Shell discoidal ; whorls separate ; outer margin sometimes 

 foliaceous. 



SxoiiATELL.^, Lam. 



Etymology, diminutive of stoma, the aperture. 



Tyx>e, S. imbricata. PI. X., Eig. 19. 



Shell ear-shaped, regular; spire small ; aperture oblong, very 

 large and oblique, nacreous; lip thin, even-edged; operculum 

 ciixular, horny, multi-spiral. On reefs and under stones at 

 ow water. 



Distribution, 33 species. Cape, India, North Australia, 

 China, Japan, PhLlipi)ines. 



Sub-genus ? Gena, Gray. Spire minute, marginal ; no 

 operculum. 16 sj)ecies. Eed Sea, India, Seychelles, Swan 

 Ptiver, Philippines. (Adams.) 



Nipjlionia, Adams. 1 species, Japan. 



Brodeeipia, Gray. 



Etymology, named in honour of W. J. Broderip, Esq., the 

 distinguished conchologist. 



Type, B. rosea. PL X., Eig. 20. 



Shell minute, limpet-shaped, with a posterior sub-marginal 

 apex ; ai')erture oval, as large as the shell, brilliantly nacreous. 



Distribution, 3 species. Philii^pines ; Grimwood's Island, 

 South Seas. (Cuming.) 



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