448 



Birge — The Crustacea of the Plankton. 



Table J. — Chydorus. — Average, maximum, and minimum numbers, 

 Percentile vertical distribution. 











Per cent, in each 3 



M. LEVEL. 





Av. 



Max. 



Min. 























0-3. 



3-6. 



6-9. 



9-12. 



12-15. 



15-18. 



1894. 





















Sept. 16-30.. 



278.9 



440.7 



96.6 



55.0 



26.9 



10.6 



5.6 



2.0 



0.0 



Oct. 1-15.... 



193.3 



251.2 



92.8 



12.3 



13.3 



16.4 



21.6 



21.6 



14.8 



Oct. 16-31... 



202.0 



304.6 



82.0 



14.2 



17.8 



18.0 



18.7 



19.9 



11.3 



Nov. 1-15.... 



97.9 



261.3 



13.3 



7.3 



15.5 



18.6 



28.4 



19.3 



10.8 



Dec. 1-15.... 



9.5 



15.9 



3.8 



16.7 



20.6 



13.3 



16.7 



18.7 



14.0 



1895. 







i 















June 1-15 . . . 



36.7 



92.8 



11.1 



41.9 



24.9 



13.0 



9.4 



5.0 



5.6 



June 16-30 . . 



21.9 



45.7 



6.9 



83.1 



13.4 



2.4 





1.1 



0.0 



July 1-15.... 



156,8 



271.5 



13.3 



61.1 



25.3 



11.0 



2.2 



0.4 



0.0 



July 16-31... 



163.4 



283.6 



89.0 



42.8 



35.2 



20.3 



1.2 



0.2 



0.2 



Aug. 1-15 . . . 



78.6 



157.7 



16.8 



43.2 



30.4 



18.4 



7.3 



0.5 



0.1 



Aug. 16-31 . . 



18.7 



48.7 



5.0 



32.7 



33.3 



21.8 



11.2 



1.1 



0.0 



Sept. 1-15... 



15.6 



39.4 



8.9 



45.5 



23.6 



22.8 



4.8 



3.4 



0.0 



Sept. 16-30., 





Scatte 



ring 



only. 













Oct. 1-15.... 



8.6 



14.3 



5.0 



17.6 



17.6 



6.6 



12.5 



14.7 



30.9 



Oct. 16-31... 



8.1 



12.0 



3.8 



46.8 



14.1 



7.8 



23.5 



7.8 



0.0 



Nov. 1-15.... 



25.9 



46.4 



10.8 



11.4 



15.3 



14.3 



24.3 



21.3 



13.4 



Nov. 16-30... 



19.7 



29.8 



13.9 



9.2 



18.8 



24.0 



21.6 



16.1 



10.3 



Dec. 1-15.... 



15.9 



19.7 



12.0 



26.0 



6.6 



18.2 



10.5 



16 8 



22.0 



Dec. 16-31... 



20.9 



36.8 



8.9 



23.0 



18.6 



11.8 



22.6 



17.6 



6.3 



1896. 





















May 1-15.... 



28.0 



48.3 



19.0 



15.9 



23.4 



23.8 



16.2 



8.9 



11.8 



May 16-31... 



30.8 



68.6 



13.3 



34.0 



23.6 



15.9 



19.9 



4.3 



2.3 



June 1-15 



87.6 



279.8 



4.4 



77.6 



15.8 



4.7 



1.0 



0.4 



0.3 



June 16-30.. 



230.8 



346.0 



145.6 



65.0 



24.4 



7.0 



2.6 



0.5 



0.3 



July 1-15.... 



382.0 



661.4 



169.8 



57.0 



33.6 



6.9 



2.0 



0.3 



0.0 



July 16-31... 



245.1 



465.5 



129.1 



43.2 



34.1 



20.0 



2.7 



0.2 



0.0 



Aug. 1-15 



Aug. 16-31 . . 

 Sept. 1-15 . . 



406.5 

 426.0 

 748.6 







54.8 

 32.4 

 34.9 



32.0 

 36.2 

 26.7 



10.4 

 21.0 

 17.0 



2.2 



8.5 



15.2 



0.5 

 1.7 

 5.6 



0.0 







0.1 







0.7 



Sept. 16-30.. 

 Oct. 1-15.... 



263.0 

 423.7 

 191.9 

 62.7 

 69.3 

 38.2 

 28.1 







25.0 

 10.3 

 16.9 

 18.7 

 21.3 

 15.0 

 12.8 



14.8 

 15.0 

 18.1 

 22.4 

 12.0 

 16.2 

 25.0 



14.9 

 25.8 

 17.1 

 13.0 

 26.7 

 13.4 

 15.0 



12.2 

 21.0 

 12.8 

 13.4 

 17.3 

 19.1 

 17.6 



18.1 

 14.5 

 16.6 

 12.7 

 10.6 

 16.2 

 19.6 



14.9 







13.4 



Oct. 16-31... 







18.4 



Nov. 1-15 . . . 







19.8 



Nov. 16-30 . . 







12.1 



Dec. 1-15.... 







20.1 



Dec. 16-31... 







10.0 











