142 THE AMERICAN MIDFAND NATURALIST 



main channel by rocks. Found cyclops, arcella, difflugia and 

 diatoms. Life very sparse. 



Towing No. 3 was taken from a quiet pool in the creek below 

 the cemetery, the spot being well shaded. Contamination from 

 all the sewers from the cemeter)^ and below was present at this 

 point. No vegetative forms were present. 



1. Annulata{Nais) . 



2. Amoeba proteus. 



3. Diatoms (numerous). . 



4. Rotifera {Brachionus enlzii) numerous. 



5. Paramecium. 



6. Arcella. 



7. Euglenoidea very abundant and this is indicative of sewage contam- 



ination; encysted forms abundant also. 



More forms found here and the species were more numerous than 

 at the points from which the two preceding towings were taken. 



Down about 150 feet the vegetation was chiefly of a chara-like 

 plant' Rapids were located below the second point of collection. 

 In the rapids we found snails (numerous) larvae cases of midges, 

 nematodes, beetles. 



From rock on bottom: plannaria, caddice fiy cases, bryozoan, 

 snail eggs, fly larvae, Q:gg case of water beetle, leech and hydra. 



Air temperature was 30 degree C. and that of the water was 35. 



Lake Erie Plankton. 

 July 27, 1916. 



Towing No. i at surface. 

 3 Vorticella on blue-green algae (Anabaena Flos-aquae). 

 2 Diatoms. 



Towing No. 2. ^ distance to bottom — 10 feet. 

 12 Naiiplius. 



2 Cyclops. 



I Bosmina. 

 18 Vorticella on Anabaena Flos-aquae. 



Towing No. 3 taken from the bottom — 20 feet. 

 4 Daphnia hyalina. 

 65 Cyclops. 

 20 Naiiplius. 



There were few forms found at the surface, more numerous 

 at the middle and bottom, greatest number at the bottom. The 

 adult Cyclops most numerous at the bottcm while the nauplius 

 stage was found to be rriost abundant ^' distance to the bottom. 



