Occasional Papers of ihc Mitsciim of Zoology 5 



bottom was originally clean sand, but admixture with organic 

 debris had made it rather mucky in places. Water-lilies grew 

 plentifully in the deeper parts, bordered with irregularly dis- 

 tributed bunches of Vallisneria and Potamogeton, while sedges 

 grew rather thickly in the shallower parts of the cove. 



Amphipods, Odonata, various beetles ( Dytiscidae, Gyrini- 

 dae, Donacia), tadpoles, frogs, and schools of young hsh were 

 common here. 



Station V was a small oval beach pool, about twenty by 

 sixty feet in extent, on the north shore of the lake near North 

 Fishtail Bay. It was separated from the lake by a low sandy 

 bank, beyond which a new^ beach pool was forming. The 

 w^ater here was only about eight inches deep, and rather turbid. 

 The aquatic vegetation was fairly dense, and covered nearly 

 the entire area of the pool: it consisted chiefly of Scirpus. 

 Kquisetum, and Carex. The fauna consisted principally of 

 beetles, Odonata, Hemiptera, and Arachnoid forms. 



Station VI was the larger of two adjacent beach pools on 

 the north shore of Douglas Lake, which are known locally as 

 the Sedge Pools. This pool, which proved to be the best sta- 

 tion in the Douglas Lake region for collecting Hemiptera. was 

 about 200 by 75 feet, with a central area of open water about 

 120 by 50 feet in extent. The water was about two feet deep 

 in the center of the pool, and slightly turbid ; and the bottom 

 was very mucky, underlaid with sand. The aquatic vegetation 

 around the open water was composed principally of Nym- 

 phaea, Sagittaria, Scirpus, Equisetum, and Carex, with some 

 Phragmites, Vallisneria, and plants of similar habit ; and along 

 the north shore of the pond there was a thicket of willow and 

 dogwood coming down to the water's edge. In the open water 

 there was a small growth of submerged vegetation, consisting 

 of a s])ecies of Potamogeton. 



