446 Birge — Vertical Distribution of Pelagic Crustacea. 



Table G — Table showing the percentage of each form of Crustacea by 



periods and levels. 







Diaptomus. 











Cyclops 







Depth. 



Period. 



Period. 



Meters. 



I. 



H. 



III. 



IV. 



Av. 



I. 



II. 



III. 



IV. 



Av. 



0—3... 



84.0 



75.6 



62.68 



57.5 



69 



10.57 



22.5 



33.92 



38.2 



26 



3—6... 



83.87 



68.5 



61.24 



53.4 



65 



10.75 



28 



35.42 



42.4 



31 



6-9 .. 



72.32 



57 



59.72 



52.8 



59 



16.7 



30.6 



32.20 



42.1 



32 



9-12.. 



41.78 



22.9 



28.89 



50.9 



36.5 



26.49 



49.4 



61.48 



42.5 



48.3 



12 — 15.. 



20. 



2 



6.25 



63 



11.5 



31.2 



54 



83.33 



37 



55.7 



15—18 . 



69.56 



78.56 



83 

 69.3 



33.33 



55 



57 



8.70 

 12.92 



17 

 26.2 



66.67 

 36.15 



33 

 40.5 



30 



Av... 



59.26 



53.3 



64 



30.5 





Daphnia 



hyalina 









Daphnia pulicaria. 





Depth . 



Period. 



Period. 



Meters. 



I. 



11. 



HI. 



IV. 



Av. 



I. 

 ,05 



II. 



.08 



III 

 



IV. 



Av. 



0-3. . . 



5 37 



1.7 



3.4 



4.1 



3 







.06 



3—6... 



5.09 



2.9 



3.17 



4 



3.4 



.28 



.5 



.17 







3 



«— 9... 



7.68 



5 



3.32 



4.5 



4.6 



3.29 



6 



4.75 



.4 



3.7 



9-12.. 



16.42 



2.1 



.74 



3.6 



3.5 



12.31 



25.5 



8.89 



2 9 



11.5 



12—15.. 



11.11 



2 



6.25 







4 



37 78 



3.9 



4.17 







30.7 



15-18.. 



13.03 





 2.3 





 3.15 



11 



14 

 3.3 



8.7 





 2 















Av... 



6.44 



4.2 



2.08 



1.44 



.3 



1.5 



THE DISTRIBUTION OF THE CRUSTACEA IX DETAIL. 



Diaptomus oregonensis Lillj. 



Number. — -This species was by far the most numerous of the 

 Crustacea ta&en during July in lake Mendota, and at the same 

 time was the species whose vertical distribution was most dis- 

 tinctly marked. The average total catch of Diaptomus for the 



