.'l.V. On the genus Pompholyx and its Allies, 



Sub-genus Tsidora. Ehr. 1831. 



Shell with the whorls inflated, columella destitute of a fold, 

 Bemi-umbilicated. 

 Type Isidara contorta= Physa contorta. Mich. 



Sub-genus Anuria. II. Adams. 18*51. 



Spire short; whorls appressed, flattened, tabulate or carinate 

 posteriorly. Last whorl much the largest. 



Example, Ameria scalaris = Paludina scalar is. Jay.* 

 Tampa Bay, Fla. 



Sub-genus P/iysodon. Hald. 1853. 



Shell solid, smooth, columella toothed, outer lip thickened. 

 Type Physodon microstoma. Hald. 



Genus Macrophysa. Meek. 18G5. 



Spire very much elongated, whorls numerous, nearly equal ; 

 body whorl short ; aperture less than one-fourth the length of 

 the slender, evlindriform shell ; apex obtuse. 



Type Marrojthysa columnar is = Physa cohonnaris. Desh. 



Fossil in the Eocene of the Paris Basin. 



Q-enus Btilinus. Adans. 17.">7. (Aj>h\ra, Flem.) 



Mantle edge simple. Buccal plate cartilaginous. Tentacles 

 long, filiform. 

 Shell sinistral, elongate; margin of aperture entire. 

 Type Bulihus hypnorum. Linn. 



Genus Physqpris. Krauss. 1848. 



Shell ovate, thin; 'Miter lip acute, columella plicate, invo- 

 lute. Soft parts unknown. 

 Type Phytopsis qfrioana. KJranss. 



• A careful examination of a number of HpecimeiiH of thi« singular form 

 hhdWH tliat it i- distinct, and not a younjf PkMOTbit, as DM been Huspected. 

 M"-t of the npeciuH of thin group are from the Southern Hemisphere. 



