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The Ohio Journal of Science [Vol. XIX, No. 8, 



to be found along the shores of ponds. The shore-inhabiting 

 coleoptera and the odonata nymphs found in the pool region 

 frequent situations which furnish protection either in the form 

 of small stones and debris or in the form of a yielding substra- 

 tum. Much the same holds true for ephemerid nymphs and such 

 snails as Physa. It will be noted that both of these were repre- 

 sented at Station 3 which is that part of the main pond approach- 

 ing suitable conditions for them. 



A view of the Five Year Pond. 

 The shallow pools are not visible. 



A pond in the state of development attained by this one 

 is thus seen to offer an environment primarily suited to pelagic 

 forms, and the animals actually inhabiting it are largely of this 

 type. The total absence of pelagic insects, as previously 

 pointed out, is to be attributed to the fishes. However, when 

 we consider all of the pond, both shallow and deep waters, 

 insects far outnumbered any other class. This statement is 

 perhaps not entirely fair to the protozoa, a careful tabulation 

 of which was not attempted. Aside from these microscopic 

 animals the insects composed forty per cent of the total 

 population. 



