190 ILLINOIS STATE ACADEMY OF SCIENCE 



animals increase. Animals are dependent upon eacli 

 other; some snpply food, some are enemies, etc. Man 

 likewise has mnch influence upon the life of the pond. 

 Animals also are dependent upon the amount and kind 

 of vegetation, for plants are used for places to secure 

 food, clinging places, sources of oxygen, shade and 

 breeding places. 



Animals thus form communities according as they se- 

 lect the same kind of habitat. In ponds the following 

 habitats may usually be recognized. (1) The littoral or 

 shallow water area along the shore comprising both that 

 of (a) emergent vegetation and (b) that of submerged 

 vegetation; and (2) the pelagic or open water area where 

 fixed vegetation is lacking. The plants and animals of 

 this area are called Plankton. They remain suspended 

 on the surface of the water. There may be another open 

 water society called Necton which refers to large free 

 swimming forms. The emergent vegetation area is lack- 

 ing in Lake Knox, but is evidenced in the muskrat region. 

 The area of submerged vegetation is found on the north 

 side, where Elodea is rather abundant and also at Sta- 

 tion V where algae are so abundant. 



GENERAL SURVEY OF THE FAUNA OF LAKE KNOX. 



Phylum Protozoa 



All the protozoa identified were found in an aquarium of water 

 collected from the pond. 



1. Sarcodina 



Class Rhizopoda 



Only two classes of the so-called pseudopodia bearing 

 organisms were found. 

 Amoeba proteus 



These were few In number. 

 Arcella vulgaris 



This is a green, smooth shelled RMzopod. They were not 

 abundant. 



2. Mastigopliora, the flagellates 



Euglena viridis 



Only one specimen was seen. 

 Volvox 



Was rather more abundant. 



3. Infusoria 



Class Ciliata 



Order Holotricha 



Two specimens of Paramoechcm were found. 

 Paramoeciuvi caudattim. a large protozoan, was very abundant 

 on the surface of the small jar of water. The specimens 

 were so large that they were easily seen with the naked eye. 

 Paramoccium aureUum 



Was found in a similar situation though not so abundant. 



