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NATURE-STUDY REVIEW 



[10:6— Sept., 1914 



sufficiently firm bottom-soil, so that wadinj^: can be done easily 

 with ordinary rubber boots. During ordinary seasons, the water 

 dries off completely in summer, and it is probably exceptional for 

 the ponds to contain water for the entire year, so they are temporary 

 in character. 



Aquatic insects, adults and larvae, form a conspicuous part of the 

 animal life of the ponds. Especially noticeable forms are, dragon- 

 flies, damsel-flies, water-striders, whirl-i-gig beetles, back-swim- 

 mers, water-boatmen, diving-beetles, and water-scavenger beetles. 



Fig. 4. Prairie Pond in Summer, showing Zones of Vegetation 



Crustaceans are represented by many crayfish and large numbers 

 of entomostracans, including big, red copepods, an eighth of an 

 inch or more in length, that swarm by the thousands in the water 

 during the early spring. Mollusks are prominent; a large 

 LymncEa with a long, spiral shell, some inch and a half in length, is 

 the most noticeable form. Besides this there are many individuals 

 of Physa and Planorhis. Some leeches and sponges have been 

 found in the ponds by the writer as well as a few other of the larger 

 invertebrates. 



Not many kinds of aquatic vertebrates are present in these 

 ponds. No fish have been found due chiefly to the temporary 

 nature of these bodies of water and to the fact that they are not 



