FAMILIES OF PULMOBRANCHS. 

 Family I. Lymn^ana. 



These wayside creatures dwell 

 In fens or marshes ; hence their simple shells 

 Are thin and smooth, for little strength they need, 

 And theii' dull habitat clothes them in suit of gloom. 



The LymncBana constitute a small family of air-breath- 

 ing mollusks^ which live in water. They chiefly inhabit 

 fens_, and stagnant pools,, and wayside ditches^ beside which 

 the marsh-marigold and bright blue mouse-ear often 

 attract the passer-by. Those who stand on the margin of 

 such stagnant or sluggish waters^ may observe small bubbles 

 on their surface, occasioned by the sudden emerging of these 

 strange mollusks, in order to breathe freely. And yet they 

 are endowed with the singnlar faculty of occasionally sus- 

 pending their respiration for a longer or shorter period, 

 according to need. When, therefore, their homes — the 

 marshes, or wet ditches — become dry during the heat 

 of summer, they are enabled to await, without injury, the 

 return of rainy weather, on which the humidity of their 

 location generally depends. 



