160 



THE AMEBIC AN NATURALIST [Vol, LI 



No. 1. Characteristic marsh pools. 



No. 2. Clear cold lakes and streams with no plant life. 



No. 3. Clear springs and streams with plants abundant. 



No. 4. Small, clear pools containing organic sediment 

 in decomposition and fed by pure, cold rills. 



No. 5. Ditches and pools choked with algae, water warm. 



All of the material was taken during the months of late 

 spring, summer, and early fall, while the aquatic vegeta- 

 tion, and the semiaquatics about the water margins, were 

 in vigorous growth. 



Envikonmental Type No. I : Marsh Pools 

 Characteristic frog-inhabited marsh pools, containing 

 much decaying vegetable matter, supporting rank growths 

 of typical marsh plants about the margins, covered with 

 lily pads and filled with Ceratophyllum, Myriophyllum, 

 Sagittaria, duckweed, etc. Water warm, and emitting 

 characteristic swampy odor. 

 Predominant forms: 



Bifflugia acuminata, Ti\imeTO\x% Vorticella microstoma, numerous 



Difflugia corona, numerous Vorticella nutans, numerous 



Other forms present in less numbers (few or rare) : 



Actinophrys sol Euplotes carinata 



Arcella dentata Euplotes charoyi 



Bactylosphcerium radiosum Pleuronema sp. 



Dinomonas vorax Prorodon griseus 



