126 PHYSA. 



PhysellA, Haldeman. Shell globose, spire 

 short ; aperture elongate, very wide ; columella 

 with the fold well marked. 



The peculiar globosely inflated form of this 

 genus recalls forcibly the genus AmpJiipmplea, 

 from which it differs principally in being sin- 

 istral. 



Phtsodon, Haldeman. Shell solid, smooth, 

 elliptical ; outer lip thick ; columella toothed. 



IsiDORA, Ehrenberg. Shell ovate, umbili- 

 cated ; columella without a fold. 



Ameria, H. Adams. Shell with the whorls 

 flattened, and angulated or carinated at the 

 posterior part (spire) ; spire short, depressed. 

 This subgenus, proposed in 1861 for a group 

 of Australian species, may also receive a single 

 American species. Ph. scalaris, Jay. 



CoSTATELLA, Dall. Shell oblong, covered 

 with longitudinal elevated equidistant ribs. 

 Soft parts unknown. 



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