ANIMALS AND THEIR ENVIRONMENT 



295 



furnish additional surface to which aquatic animals may cling. One of 

 the chief characteristics of pond life is that it must be prepared to dry up. 

 Typical pond organisms are those which spend part of their life cycles out 



Fig. 261. — Ponds; large one above with vegetation practically throughout, snaall one 

 below with heavy vegetation completely concealing the water. {Photographs by F. C. 

 Gates.) 



of water, either m a resting condition or actively in the air or on land. 

 The larger ponds are permanent, and the organisms in these approach 

 those of lakes in their characteristics. Ponds are temporary bodies also 

 from a long-range point of view sinccj as explained above, they are being 



