LIMNEUS, 



GENERIC CHARACTER. 



Shell oblong, ovate, oval, conic or turrited, thin, smooth : 

 spire prominent, more or less elongated : aperture more 

 or less dilated, longitudinal, entire ; columella at its supe- 

 rior part or junction with the labium entering the aperture 

 hy a very oblique fold or undulation; labrum acutely 

 €dged ; operculum none. 



''Animal oval, more or less spiral ; margin of the mantle 

 thickened on the neck ; foot large, oval ; head with two 

 triangular, compressed^ earshaped tentacula ; eyes sessile, 

 at the inner base of the tentacula ; mouth with two late- 

 ral appendices, and armed with a superior tooth ; orifice of 

 the pulmonary cavity on the right and bordered by 

 an appendage which can be folded in gutter ; orifice of the 

 reproductive organs distant ; that of the oviduct at the en- 

 trance of the pulmonary cavity ; that of the male organ 

 under the right tentacula." — (Blainville.) 



OBSERVATIONS. 



A numerous genus of fresh water shells, inhabiting al- 

 most every part of the globe. The species known to 

 Linne were placed in his great reservoir Helix ; in which 

 he has been followed by many of the English Concholo- 

 gists,even of late years. Bruguiercs, eminent for his use- 



Pl. 31. 



