Life in Some Typical Lenitic Situations 333 



ing in social functions to the larger beasts of the forest, 

 so in the water there are large and small, assembled in 

 parallel associations. The larger, as a rule, inhabit the 

 more open places. Paddle-fish and sturgeons and gars 

 belong to the rivers; the quantative demands of their 

 appetites exclude them from living in the brooks There 

 is not a living there for them. Little fishes belong to 

 the brooks and to the shoals. In our diagram on page 

 233 we have already shown how in a small lake shore- 

 ward distribution of the fishes corresponds roughly with 

 their size, the largest ranging farthest out, and the 

 smallest sticking most closely to shelter. The senior 

 author has shown (07) a parallel to this in the distribu- 

 tion of diving beetles in an angle of the shore of a weedy 

 pond. Here the most venturesome beetle was Dytiscus 

 (see fig. 129 on p. 221). It was taken at the front of 

 the cat-tails in about three feet of water. The associa- 

 ted species were disposed closely, tho not strictly in 

 accordance with their size, between that outer fringe 

 and the shore, Acilius, Coptotomus, Laccophillus, 

 Hydroporus, (see fig. 130) Coelambus and Bidessus 

 following in succession, the last named (a mere molecule 

 of a beetle, having but -^Att the weight of Dytiscus) 

 being found only among the trash at the very shore line. 



LIFE IN SOME TYPICAL LENITIC SITUATIONS 



The association of organisms in natural societies is 

 controlled by conditions; but conditions intergrade. 

 Lakes, ponds, rivers, marshes all merge insensibly, 

 each into any of the others; and their inhabitants 

 commingle on their boundaries. Yet these names stand 

 for certain general average conditions that we meet 

 and recognize, and with which certain organisms are 

 regularly associated. It will be worth while for us to 

 note the main characteristics of the life of several of the 

 more typical of such situations. 



