PLATE J. 



Ceriodaphnia scitula^ (small var.) ephippial female. 

 Bosmina longirostris. 



Bosmina lilljehorgii. After P. E. Mueller. 

 Bosmina^ hook on the first foot of male. 

 Scapholeberis m ucronata . 

 Scapholeberis cormita, head. 

 Scapholeheris angulafa, head; 7a. angle of shell. 

 Pleuroxus denticulatiis, male. 

 Simocephalus americamis, head of female. 

 Fig. 10. Bosmina, post-abdomen of male (after Weismann). 



