132 



116. Valvata Planorhis. Shell flat above, and 

 deeply umbilicate beneath. 



Valvata Planorbis. Draii. p. 41. t. \.f. 34, Q5. 

 Brard,p. 186. t. Q.f. 18, 19. 



Shell smaller than the last, from which it differs in 

 being of a more transparent whiteness, and not 

 being concave or sunk in the upper surface ; the 

 umbilicus is also narrower and deeper. 



Found with the last, but more rarely. 



117. \ xjuXATX m'lnuta. Shell a little convex above, 

 and umbilicate beneath. 



Valvata minuta. Drap. p. 48. t. 1./. 36—38. 

 Helix serpuloides. Mont. Suppl. 147. t. 21. f. 3. 

 Turbo serpuloides. Turt. Diet. /). 228. 



Shell exceedingly minute, with two or two and a half 

 volutions, very finely striate, a little convex on the 

 upper surface, and deeply umbilicate beneath. 



Very much allied to this species is the Turbo depres- 

 sus, which we take from the marine rocks in 

 Devonshire ; but independently of the latter being 

 a salt-water shell, the operculum is not spirally 

 striate, and the animal wants the crested appendage 

 in the middle of the head. 



In ditches and marshes. 



