THE HAUNTS OF LIFE 103 



animals. It is marked by such plants as the stonewort 

 (Cham), mare's tail (Hippuris), pond- weeds (Potamogeton), 

 duckweed (Lemna), water-lilies, Ranunculus lingua, Alisma 

 pkmtago, bog-bean, and so forth. Some show interesting 

 adaptations of mobility and elasticity suited to the turbu- 

 lence of the shore. 



As to the animal life, it is varied. By the shore there 

 may be nests of gulls and wild duck, of coot and moorhen. 

 The shallows are the home of frogs and sticklebacks, of carp 

 and miller's thumb (Cottus gobio). The freshwater mussels 

 plough their leisurely way along the mud ; the water-snails 

 glide back downwards along the surface-film. The water- 

 spider weaves her diving-bell nest, and beautifully coloured 

 water-mites rush to and fro. There are countless Crus- 

 taceans, like Daphnia and Sida, Diaptomus and Cyclops ; 

 fixed Rotifers like Floscularia and Melicerta miracles of 

 beauty ; some equally fascinating freshwater Polyzoa ; 

 simple Planarian worms wafting themselves along the water 

 weed by their unseen cilia ; besides Hydra and freshwater 

 sponges and many Protozoa. We have given samples 

 enough to show that the shore of the lake has a very 

 representative fauna. 



The second great region in lakes is the open water, 

 tenanted by a pelagic or limnial fauna and flora. The 

 vegetation is represented by numerous Alga3, by duck- 

 weed and Ceratophyllum, by the beautiful rootless Bladder- 

 wort (Utricularia) with its neat traps for water-fleas. 

 Some show gas vesicles which ensure floating. As to 

 animals, there are Infusorians (e.g. species of Ceratium 

 and Peridinium), numerous Rotifers, legions of water- 

 fleas, not a few water-mites (such as Atax crassipes and 

 Curvipes rotundus), a few insect larvae, e.g. of Corethra 



