103 



the G. Achatina (to which it more properly belongs), 

 and has placed it next to the Achatina fuhninea. — 

 Sowerby has united these with the Physse, for the 

 reasons stated in the description of that genus. 

 Lymnaea columnaris Lymnaea auricularia 



stagnalis 



palustris 



Virginiana 



luteola 



acuminata 



ovata 



peregra 



intermedia 



leucostoma 



minuta. 



MELANIA. 



HELIX AMARULA. Linn. 



Mawe's Linnaeus, -plate 29>fig> 2. 

 Linn^us blended these shells with his G. Helix, and 

 some affinity has been supposed to exist between this 

 genus and that of the Lymnaea; but, except that they 

 are both of them fluviatile shells, and the form of the 

 Melania an oblong oval, with the spire produced or tur- 

 reted, in other respects they are very dissimilar. The 

 shells of this genus are closed by a horny operculum : 

 they are rather thick; the exterior wrinkled, and the 

 margin of the spiral whorls often surmounted by spines 





