GENUS PLANORBIS, Mutter. 



PLATE 1. FIGS. 1,2. 







Testa discoidea, spira valde depressa: anfractibus omni- 

 bus utrinque conspicuis: apertura lunata, ab axe remotis- 

 sima. 



SYNONYMS AND REFERENCES. 



HELIX, LINNAEUS, GMELIN, WOOD, &c. 

 PLANORBIS. MULLER, BRTJGTJIERE, &c. 

 LAMARCK. An. sans Vert., viii. p. 379. 

 DESHAYES. In the same, viii. p. 380. Anno 1838. 

 SOWERBY. Genera and Manual. 



CUVIER. An. du Mus. Memoires, Anno 1817, Regne ani- 

 mal, pi. 26, fig. 4. 



DESMOULINS. Tr. Soc. Lin. Bordeaux. Anno 1831. 

 PENNY CYCLOPAEDIA, xiii. p. 495. 



DESCRIPTION. 



ANIMAL elongated, slender, and closely rolled 

 up; head saddle-shaped and slightly emarginate, 

 anteriorly: tentacles long and setaceous; mouth 

 provided with a spoon-shaped tongue, opposed 

 to a concave tooth anterior to it; respiratory 

 orifice upon the left side. 



K 1 



