210 



Marsh — Limnetic Crustacea of Green Lake. 



DAPHNIA KAHLBERGIENSIS. 



D. kahlbergiensis did not occur in the collections from 1.96 to 7.96 . 



No. 

 of Coll. 



Total 

 No. 



0-5 



5-10 



10-15 



15-20 



20-25 



25-30 



30-35 



35-40 



40- 



8.96.. 



40 



225 



129 



71 



325 



84 



32 



5 



108 



68 



73 



86 



92 



94 



78 



223 



72 



61 



102 



16 



7.50 

 42.67 

 37.21 

 11.27 

 39.38 

 14.29 



20. 



21.92 

 37.21 

 60.87 

 34.04 

 10.26 

 46.19 

 13.88 

 59.02 

 in 

 18.75 



60. 



17.78 



18.60 



56.34 



29.54 



19.05 



62.50 



20. 



21.34 



15.50 



16.90 



24.62 



47.62 



37.50 



10. 



17.77 



24.81 



7.04 



6.15 



9.52 



2.50 

 .44 

 .78 



1.41 











9.96.. 











10.96.. 

 11.96.. 

 12.96.. 



4.22 



1.55 



2.82 

 .30 



1.55 



13.96.. 



9.52 









14.96.. 











15.96.. 









20. 



20. 



40. 



16.96.. 



3.70 



5.88 



27.91 

 8.70 

 42.55 

 30.77 

 17.94 

 22.23 

 26.23 

 0-20 

 25. 



81.48 

 35.30 



32.88 



6.52 



8.51 



35.89 



17.94 



33.34 



6.56 



met'rs 



12.50 



11.12 



35.29 



35.62 



9.30 



4.35 



8.51 



12.82 



10.76 



27.78 



6.55 



6.25 



.93 



22.06 



6.85 



10.46 



13.04 



1.07 



3.85 



5.38 



' 1.64 



12.50 



2.77 





17.96.. 





1.47 





18.96.. 



1.37 



13.96 



3.26 



4.26 

 2.57 



.89 



2.77 



1.36 

 1.16 

 2.17 

 1.06 

 2.56 

 .45 





19.96.. 







20.96.. 

 .21.96.. 



1.09 





22.96.. 

 23.96.. 

 24.96.. 



1.28 



.45 



25.96.. 









26.96.. 

 27.96 



25. 

















During the fall of 1894 (see PI. XI) the collections of 

 Daphnia kahlbergiensis were quite uniform in amount, reaching 

 a maximum in the latter part of October. During the winter 

 the number was very small, and they did not become numerous 

 again until June. There is a fall maximum again in 1895 in 

 the latter part of October, but, curiously, the total numbers 

 collected during the fall of 1895 are much smaller than in 1894. 

 During the winter and spring of 1896 Daphnia*w&s entirely ab- 

 sent from the collections. They appear again about the middle 

 of May, and the largest collections of the year were made from 

 June 29 to July 27. In August and September the collections 

 were rather small, but the number became larger the latter part 

 of October as in the preceding years. 



Apstein ('96, p. 170) states that the species of Daphnia reach 

 their maximum in August, but that D. cederstroemi is somewhat 

 later, so that it would appear that my results in regard to the 

 seasonal distribution of Daphnia do not agree very closely with 

 his. It is probable that the various species of Daphnia may 

 differ considerable in their periods of maximum occurrence. 



