PALUDINA. 



GENERIC CIIAnACTER. 



Shell fliiviatile, conical, subovatc or suboval, covered by 

 an epidermis ; spire moderate ; whorls convex ; aperture 

 longer than broad, angulated above, simply rounded at 

 base ; labrum simple, acute, united above to the extrem- 

 ity of the labium ; labium simply arquated ; operculum 

 corneus or coriaceous, suborbicular, slightly angulated 

 above. 



OBSERVATIONS. 



The spccie.s of this genus were widely separated from 

 each other by former authors, and referred to the Genera 

 Hel'ix^ Turbo, BuUmiis, Nmta, and Cydostoma; but La- 

 marck selected and embodied them under the present de- 

 signation, and they now constitute a natural group. 



They may be distinguished from CycloHtoma by the 

 simple labrum, as well as by other charactei-s of the shell, 

 a.s also of the animal, from Mclania by the simple curva- 

 ture of the labrum at base, and from Valvala by the form 

 of the aperture which is not angulated above in that gcnu^. 



The animal has two linear-acute tentacula, with the 

 eyes at their exterior base ; anterior part of the body with 

 a small membranaceous wing on each side, the right one 

 is •■ recurved in a small canal, which introduces the wat(^r 

 into the respiratory cavity ;" " the branehiai are composed 

 of parcels of fdaments, which are attached to the sides of 



PLATE X. 



