Animals of the Mississippi Bottoms near Quincy. 183 



zoan. The animals themselves are on the outside of the 

 masses and constitute but a small part of the bulk of each 

 mass. In the upper part of the bay, in the inlets and mouths 

 of sloughs, this animal was very abundant. As the water sub- 

 sided 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 12.50 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 ofthe object 

 upon which it is established. I could not see that fishes, or 

 indeed anything else, fed upon the gelatinous material. Repro- 

 duction both by statoblasts and by eggs was in progress in 

 August. 



CCELENTERATA. 



Hydra fusca^ 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 budding. The food consists of small animals which 

 are captured by the tentacles. 



PROTOZOA. 



Notwithstanding their minuteness, the protozoa 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 veg- 

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



