Fig. 



1. 



FiiT. 



2. 



Fig. 



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Fig. 



4. 



Fig. 



5. 



Fig. 



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Fig. 



7. 



Fig. 



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Fig. 



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Fig. 



10. 



PLATE J. 



Ceriodaphnia scitula^ (small var.) epliippial female. 



Bosmina longirostris. 



Bosmina UlljeborgiL After P. E. Mueller. 



Bosmina, hook on the first foot of male. 



Scapholeberis mucronata. 



Scapholeheris cornuta. head. 



Scapholeberis angidata, head; Ta. angle of shell. 



Pleuroxus denticulatus, male. 



Simocephalus americanus, head of female. 



Bos))iina, post-abdomen of male (after Weismann). 



