112 



was very abundant. As the water subsided the masses were often 

 exposed, and were left in numbers to decompose in the air. 

 One of the largest masses seen measured 16.50 inches in greater 

 diameter by V2.50 inches in lesser diameter, with an average depth 

 of about six inches. Small spindle-shaped colonies were common 

 on the stems of dead weeds along the margins of the lakes. The 

 shape of the colony seems to depend entirely on the character of 

 the object upon which it is established. I could not see that 

 fishes, or indeed anything elsfe, fed upon the gelatinous material. 

 Reproduction both by statoblasts and by eggs was in progress in 

 August. 



CCELENTEEATA. 



Hydra fiisca, Trembley. 



These small animals are the closest allies of the corals and sea 

 anemones of salt water, which our streams and lakes furnish. They 

 are, when extended, about .25 inch long, and consist of a tubular 

 body with a circle of tentacles about the one opening, the mouth. 

 They are commonly found attached by the end opposite the mouth 

 to plants and other submerged objects. I was surprised to find 

 them on one occasion in Wood Slough in considerable numbers, 

 and took others with the surface net in the bay, where they must 

 have been floating at the surface. Those taken in Wood Slough, 

 Aug. 4, were multiplying very rapidly by bud'^liug. The food con- 

 sists of small animals which are captured by the tentacles. 



PROTOZOA. 



These are the lowest and simplest of animals. They are unicel- 

 lular, and chiefly microscopic. Notwithstanding their minuteness, 

 they are of considerable importance as fish food, and are probably 

 still more useful indirectly, since they constitute a large share of 

 the food of insects. 



At Quincy the animals of this group varied with the vegetation 

 in the water. Where the plants were common, a variety of 

 species and an abundance of individuals might be expected. In 

 the river they were very rare. In the deeper water of the bay 

 they were not as common as at its edges, among the wood rafts 

 and the barges. They were most common in the stagnant water of 

 the lakes. Such genera as Amoeba, Difllugia, Centropyxis, 

 Actinosphserium, Voticella, and Euglena were abundantly repre- 

 sented. In Lily Lake a species of Pyxieola attracted attention 

 from its abundance. It was noticed in the alimentary canal of the 

 singular Dero mentioned above. 



Two protozoans are especially deserving af mention here. The 

 elongated green' Euglena viridis was always to be found in water 

 dipped up at any place in the bay. When the wind blew toward 



