, PLATE CLXXV. 



FIG. I. 

 HELIX FRAGILIS. 



BRITTLE RIVER SNAIL, 

 GENERIC CHARACTER. 



Aperture of the mouth contracted, and lunulated. 



SPECIFIC CHARACTER 



AND 



SYNONYMS. 



Shell imperforate, ovate, tapering, round, pellucid : aperture oUong- 



ovate. 



Helix fragilis: testa imperforata ovato-subulata tereti pellacida: 

 apertura ovata-oblonga. Lirm. Faun, Suec, 

 2iSl.—G)nel. Linn. Sj/st. Nat, 3658. Sp. 129. 

 F€7in. P/. 86. 



Brown River Snail. Pult. Cat. p. 48. 



Helix fragilis is distinguished from Helix stagnalis, and one or 

 two other very analogous species of river snail by a number of slight 

 ridges which spirally traverse the whol« shell, and are in particular 



H 3 obvious 



