188 AURICULID^. 



Dr. Turton calls C. jyarvula (t. 5. f. 59.) ; and also the 

 specimens of the true C. jiarvula (according to Fe- 

 russac) found in Germany, for comparison." He 

 further observes that all the British specimens he 

 has seen, he thinks, are only varieties of C. nigricans^ 

 which, I think, the specimen fully bears out. 



Sub-order III. Limnophila. 



Eyes sessile ; tentacles two, subcylindrical or 

 flattened, simply contractile ; operculum none. The 

 organs of generation with separate external open- 

 ings sometimes close together. Fluviatile. 



The male and female organs of these animals are 

 more distinctly developed ; in this respect they ap- 

 pear to be intermediate between the hermaphrodite 

 Geophila and the unisexual Gasteropods. 



Fam. 4. AURICULID^. 



The animal with an elongated foot, an elongate 

 ringed muzzle, two subcylindrical tentacles, with 

 the eyes near the inner hinder side of their 

 base ; body spiral, placed on the centre of the 

 foot, and covered with a thin mantle with a 

 thickened edge, which is itself covered with an 

 external spiral shell, which has a plaited pillar in 

 all its ages. 

 These Mollusca appear, by habit and character, 



to be exactly intermediate between the land and 



