i i ; i i 1 1 1 1 i i . 1 I " 



GtaiM FASHGIEU L8, 



Perforate, elongated. tuiTetrd; \\horl- numerous OOHVeX, with 

 spiral riMrts; aperture trrminatinir in a .-hort, -lightly tui-t.-l 

 canal. 



One or two recent speciee occur in the West [ndie*, and several 



|o->il> from the I-]. .cciic of the Paris basin arc also referred liere. 



Genoa HITTH'M (Leach ,Gy, 1847, 



Shell elevated, with numerous granular whorls and irregular 

 varices ; anterior canal short, not recurved ; inner lip simple, outer 

 lip not reflected, usually with an exterior rib. OperCulfUD fbur- 

 whorled with central nucleus. 



Animal with lanceolate foot, subtruncate in front; eyes placed at 

 the external base of the rather long tentacles ; operculigeroua lobe 

 with rudimentary expansions on the sides , >iphon rudimentary, 



Numerous small species inhabiting temperate waters. 

 Cerithiolwn, Tiberi, 1869, and Platygyra, M>rch, 1860, an- 

 synonyms. 



Section Ci:i;rnm>ir.M, Monts., 1884. 



Mouth somewhat rounded, scarcely showing any canal below. 

 ('. SIT.M. \.MII.LATI-M, Kayn. 



Genus POTAMIDES, Brongniart, 1810. 



Imperforate, turreted, angulated, tuberculate, spiny, etc., ami 

 covered by a thick, olive-brown epidermis, apex often decollated: 

 whorls numerous, narrow, the last short; aperture channeled in 

 front, outer lip simple or thickened. Operculum corneous, multi- 

 spiral. 



Animal with subcircular foot, obtuse behind; eyes on the 

 side of the tentacles at a third or half of their length ; siphon usually 

 fringed. 



Middle tooth of the radula small with toothed margin, lateral 

 tooth larirt', Bubrhomboidal, with a rostrated base and toothed mar- 

 gin, fir-t marginal tooth narrow, with a slight posterior projection, 

 second marginal tooth sometimes elongated and simple, sometimes 

 with a large external wing (PI. 19, fig. 2). 



The type is a fossil, P. L \M \KCKI, Bronpiiart. 



Inhabits brackish and fresh waters, in Tropical countries, parti- 

 cularly swamps, and the mouths of fiveiB, where they frequently 

 remain for long periods out of the water, and in the dry sea.-'>u 



