LIMNJEADJG. 



197 



The following Table respecting the eggs of Lim- 

 nceada is drawn up from M. Bouchard's observations, 

 the first column giving the form of the masses of 

 eggs, the second the number of eggs in each mass, 

 the third the number of days after they are laid 

 before they hatch. 



It had been supposed that the shells of fluviatile 

 Mollusca could be distinguished from those of the 

 terrestrial kind, by the edge of the mouth of the 

 shell never being furnished with a thickened in- 

 ternal rib, and not being in the slightest degree 

 reflexed, and that the animal never closes it with an 

 epiphragm ; however, further examination has shown 

 that when the Pond-snails and the Whirl-shells are 

 left nearly dry by the evaporation of the water, 

 o 3 



