FRESH-WATER MOLLUSKSo 83 



In many brooks you can find lively little 

 creatures with thin, horn-colored shells like Fig- 

 ure 34. Notice that the opening is on the left 

 side, while almost all shells open on the right. 



Figure 88. 



Again, you may find shells that are rolled up in 

 a flat coil, like Figure 35. 



The name of these flat snails is Planorbis. In 

 some lakes, or even some ponds, there are also 

 creatures with thin shells shaped like Figure 36 

 or Figure 37. These are the pond-snails, called 

 Limnsea, and they are found all over the world. 



