CYCLOSTOMA. PLANORBIS, 41 



C. SULCATUM of Draparnaud. Ovate-conoid, 

 yellowish or reddish flesh-colour_, spirally fur- 

 rowed, and decussated by most minute longi- 

 tudinal striae ; mouth circular, and perpendicular 

 to the axis of the shell ; lip simple, and thickish. 

 J. B. T. 76. 



C. TRUNCATULUM. Cyiindraccous ; apextrun- 

 cated, sub-pellucid, rather solid, more or less longi- 

 tudinally striated, reddish horn -colour; mouth 

 ovate ; lip reflected. ^. 



LES LYMNEENS. 



PLANORBIS. FLUVIATILE. 



Discoid, spire depressed; volutions apparent on 

 both sides; aperture oblong, and lunate; axis 

 of shell remote ; margin not reflected ; no oper- 

 culum. 



P. coRNUARiETis. Reversed, solid, flattish 

 concave and white above, beneath widely um- 

 bilicated and reddish brown ; whorls cylindra- 

 ceous, smooth ; the last banded with chestnut 

 brown; diam. l^. W. 33. 55. 



P. coRNEus. Deeply umbilicated above and 

 rusty brown, beneath flattish and w^iitish ; whorls 



