26 



Bryant Walker 



Genus LIOPLAX Troschel, 1856. 



Shell dextral, spiral, thin, ovate, turreted, imperforate, spire prodncefl ; 

 whorls rounded, or carinated; olivaceous green or dark brown; aperture 

 oval subcircular ; lij) thin, continuous; operculum concentric, with a subs|jiral 

 nucleus. 



Fi^. 81 



Fig. 79 Fig. 80 B'ig. 82 



Animal with the foot very large, greatly produced beyond the snout ; 

 snout very short. Lingual teeth smooth at their apices. 



Type: Limnaa sithcarinata Say, fig. 79. Animal, fig. 80. Operculum, fig. 81. 

 Radula, fig. 82. 



Genus TULOTO'MA Haldeman, 1840. 



Shell (typically) large, solid, thick, imperforate, obtusely conic, spire 

 elevated ; whorls flattened, nodulous, carinated ; peristome thin, continuous ; 

 operculum concentric, subtriangular, with the inner margin reflected form- 

 ing an elevated marginal fold. 



Animal with a moderate foot, not produced beyond the snout : snout 

 small ; lingual teeth multicuspid. 



Type: Paludina magnifica Con., fig. S3. Radula, fig. 84. Operculum, fig. 85. 



.-•W.'U, 



Fig. 83 



■"^\^ 



Fig. 84 



Family A^ALVATID.^. 



Fig. 85 



Shell small, spiral, dextral, turbinate, or subdiscoidal ; whorls rounded or 

 carinated; aperture entire, circular; lip simple, sharp; operculum orbicular, 

 multispiral, whorls with a thin elevated edge. 



