135 



121. VALVDi'NAsimiUs. Shell conic, yellowish horn- 

 colour, smooth, semitransparent, with five very 

 tumid volutions, and a small oblique umbiKcus. 



Cyclostoma simile. Drap. p. 31. t, 4./. 15. 

 Turbo laevis. Walker, jig. 3S. 



Shell a quarter of an inch long, and two lines broad, 

 with four or five very tumid volutions : aperture 

 dilated, nearly circular, projecting more outwardly, 

 or out of the line of the columnar axis, with a small 

 umbilicus behind it. 



The fry of this species are disposed on a tough strap- 

 shaped green membrane, in a double row, consist- 

 ing of six or seven pairs placed opposite to each 

 other ; and this elongated receptacle is fixed to the 

 under surface of aquatic plants. 



In ditches and canals. 



122. Paludina viridis. Shell somewhat conic and 

 obtuse, inflated, smooth, with four tumid volutions, 

 and no umbilicus. 



Cyclostoma viride. Dra/). p. 37. t. l.f. 26, 27. 



Shell two tenths of an inch long, and half as much 

 broad, greenish horn-colour : spire composed of 



