13 



PALUDINA PONDEROSA, Say. 



Plate 4. 



P. testa, ponderosa, subconica, laevigata; striis transversis 

 ininutissime corrugatis: apice obtusa: anfractibus convexis: 

 sutura valde impressa: lineis longitudinalibus recurvatis: 

 apertura ovato-oblonga. 



SYNONYMS AND REFERENCES. 



P. ponderosa, Say. Jour. Acad. Nat. Sc, vol. ii. p. 173. 



,, ,, Amer. Conchology, pi. 30, fig. 1. 



Sowerby's Genera of Shells, fig. 2. 

 Deshayes' Lamarck, vol. viii. p. 516. 



DESCRIPTION. 



Shell ponderous, subconic, and polished, 

 having from six to seven complete whirls: spire 

 lengthened: suture deeply impressed, and ca- 

 naliculate: aperture oblong ovate, narrowed 

 and rounded posteriorly: labium thickened, and 

 conspicuous: lines of growth undeviating until 

 near their anterior extremity, where they are 

 recurvent; labrum much advanced at this part: 

 surface with very fine transverse wavy striae, 



