442 



The Ohio Journal of Scie?ice [Vol. XIX, No. 8, 



was visible for nine feet and three and one-half inches. The 

 temperature of the water just beneath the surface was 28° C. 

 At a depth of five feet it was 27° C. and ten feet down it was 

 21° C. 



Station 1. The character of this station is shown on page 

 441. The side of the pond was a perpendicular face of practically- 

 bare rock. The water was between eight and nine feet deep. 

 The only sign of vegetation was a sparse growth of filamentous 

 algse on the rock. On the bottom there was about one-fourth 

 inch of sediment composed chiefly of quarry dust. 



The species at this station are given in Table 7, below. 

 The plankton and the nekton are not included, these being 

 treated at another place for the whole pond. It will be seen that 

 the number of forms was decidedly limited, although individ- 

 uals were numerous in some cases as, for instance, the nematodes 



TABLE 7. 



and the larvse of the midges Chironomus and Tanypus. The 

 entomostracan, Cypridopsis vidua, was also found in abundance. 

 Nais was scarce and so was Vorticella. 



This station was characteristic of three-fourths of the shore 

 line in its physical features as well as in its animals and plants. 

 A similar environment on the opposite side of the pond, the 

 far side in the photograph on page 448, differed in that at places 

 the water was not as deep and the bottom was covered with 

 rubble. In such locations the nests of sunfish were observed. 



Station 2. The pools shown in the foreground of the pho- 

 tograph on page 443 comprise this station. Some of these were 

 directly connected with the pond; others were formed by water 

 seeping through the intervening gravel. They were all shallow, 



