11 



PLANORBIS GLABRATUS, Say. 



PLATE 2. FIGS. 13. 



P. testa glabr&, vel subrugosa; anfractibus 5 ecarinatis 

 et cylindraceis: apertura obliqua. 



SYNONYMS AND REFERENCES. 



P. GLABRATUS, SAY. Journ. Acad. Nat. Sci., vol. 1. p. 

 280, June 1818. Nich. Encyc., 3d Am. ed., art. Conch. 

 Planorbis, No. 4. 



DESCRIPTION. 



SHELL "sinistral;* whirls about five, glabrous 

 or obsoletely rugose, polished, destitute of any 

 appearance of carina: spire perfectly regular, a 

 little concave: umbilicus large, regularly and 

 deeply concave, exhibiting all the volutions to 

 the summit: aperture declining, remarkably 

 oblique with respect to the transverse diameter. 

 Breadth nearly nine-tenths of an inch." Say. 



COLOR corneous, or light brown. 



GEOGRAPHICAL DISTRIBUTION. Say's shells were 

 from South Carolina: figs. 1 and 3 were drawn 



* Say would have considered the shell of P. corneus 

 sinistral. 



