41 Leaidlful Shdb. 



water. In brooks, as well as in stagnant pools, 

 wliicli abonnd with aquatic plants, they may he 

 found in vast numbers, feeding upon the moist 

 vegetation. 



The Common Limnea (Zy. sfarjnaUs) is mostly 

 an inhabitant of stagnant waters, where it is often 

 seen floating with the shell reversed, as in a boat ; 

 this shell, like most of those of the Fresh-water 

 Mollusks, is thin, and easily broken ; the shape, it 



will be seen, is peculiarly elegant, the spire being 

 slender and pointed — very different from that of 

 the Spreading Limnea, called by naturalists, L. 

 auricuJaria, from aiiriis — the car, to which the 

 broad aperture, or opening of the shell, may he 

 compared; this resembles the other species in its 

 habits. The Horny Planorbis, in Latin P. corneus, 

 from cornu — a horn. The shape, you will see, is 

 flat, the whorls rolling upon each other like tho 



