15S SPECIFIC 



PLATE XX. 



Fig. 1. Helix Scaralcsus. 



Shell ovate, two-edged, sub-umbilicate ; aper- 

 ture toothed. 



Lister Conch, tab. 577. fig. 31. 



Specimen brown variegated with pale spots, 

 outer lip and teeth horny, white ; whorls contigu- 

 ous, double convex ; aperture narrow, compressed, 

 flexuous; each lip with three teeth. 



Inhabits Asia. 



Fig. 2. II. cornea. 



Shell umbilicate, flat ; whorls four, round. 



Lister Conch, tal). 197- fig. -^l- 



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 

 umbilicate, it must also be reverse : this appears 

 upon the whole to be the fact, and the specimen is 

 therefore drawn placed upon the perforated part j 



