170 SPECIFIC 



Inhabits Asia. 



Fig. 2. H, cornea. 



Shell umbilicate, flat ; whorls four, round. 



Lister Conch, tab. 197. fig. 41. 



Specimen blackish horn-colour, longitudinally 

 striate, reverse ; apex impressed. 



Inhabits the fresh waters of Europe and Coro- 

 mandel. 



It is not easy to ascertain which is really the 

 base, and which the apex of this shell ; but if it be 

 umbilieate, it must also be reverse : this appears 

 upon the whole lo be the fact, and the specimen 

 is therefore drawn placed upon the perforated part ; 

 and the necessary alteration is made in the terms 

 of the specific description. 



Fig. 3. H. nemoralis. 



Shell imperforate, rounded, smooth, diaphanous ; 

 aperture pyriform, or irregularly lunate. 



Lister Conch, tab. 57. fig. 54. 



Specimen pale orange, margin of the aperture 

 brown ; whorls five. 



Inhabits the woods of Europe. 



