Biological Survey — Genesee River 



69 



Table 6. — ENUifERATiON ob^ Plankton Organisms Obtained from Silver 

 Lake, August 26, 1926 



Phytoplankton recorded in number of organisms per litre. 

 Zooplankton recorded in number of organisms per cubic meter. 



Net Plankton 



1-20 ft. 

 depth 



10-20 ft. 

 depth 



20-30 ft. 

 depth 



Nannoplankton 



1-10 ft. 

 depth 



10-20 ft. 

 depth 



20-30 ft. 

 depth 



Phytoplankton : 



Diatoms (mostly Asterionella), 

 Blue-green Algae 



Anabaena 



Aphanocapsa 



Chroococcus 



Coelosphaerium. . . : 



Gomphosphaeria 



Oscillatoria 



Green Algae 



Staurastrum 



Pediastrum 



Unicellular species 



Zooplankton : 

 Protozoa 



Ceratium 



Mallomonas 



Undetermined 



Rot if era 



Polyarthra 



Rattulus 



Asplanchna 



Conochilus 



Cladocera 



Bosmina 



Daphnia 



Copepods 



Cyclops 



Nauplii 



Diaptomus 



Undetermined 



2,597 



1,240 

 558 



310 



279 



31 



517 

 279 



93,000 



880 



1,653 

 558 

 248 

 124 

 186 



556 

 ""i24 



155,000 



500 



167 

 167 

 167 



333 

 167 



167 

 ,167 



500 

 500 



7,648 



1,488 

 775 



" '34i 



" "62 



1,271 



31 



181 



372,000 



1,000 



167 

 333 



333 

 667 



155,000 



333 

 248! 666 



832 



167 



93,000 



115,600 

 57,800 



2.3! 666 



34,000 

 'l7'6o6 



500 



51,000 

 41,000 



"46; 800 

 1.32,000 



'i7!6o6 



" " 167 



71,300 

 43,200 



37^006 



15,500 



217,000 



Bottom Fauna. — A number of samples of mud were taken 

 from various depths ranging* from 10 to 30 feet deep where it was 

 found that the bullheads were feeding at the time. The samples 

 were taken with a mud sampler from near the north end and also 

 from near the middle of the lake. The mud was washed to ascer- 

 tain the kinds of macroscopic animals inhabiting the lake bottom.* 

 In the soft mud between the 15 and 30-foot depths the most 

 abundant organisms were midge larvae, Chironomidae. Chirono- 

 moiis plumosus Avas the most common species, occurring in largest 

 numbers at the 25-foot depth. T any pus sp. was next in abun- 

 dance. Some small bivalve clams were also found. One of the 

 Neuroptera, Sialis sp., was found but rarel3^ 



Conesus Lake. — Conesus lake, in Livingston county, lies in a 

 shallow, north-south valley which has gradual slopes. The lake 

 is 818 feet above sea level. Its length is about nine miles and its 

 greatest width is about one mile. Near its center two streams, 



* The writer is indebted to J. R. Greeley for the identification of these 

 animals. 



