PLATE A. 



Fig. 1. abdomen of Moina paradoxa,, female, from Minnesota. 



Fig. la. spine from post-abdomen. 



Fig. 2. post-abdomen of Moina rectirostris. 



Fig. 3. head of M. paradoxa^ female, showing (a) eye with pig- 

 ment and lenses, (b) supra-oesophagal ganglion, anten- 

 nule with (c) its muscle, (d) its nerve, and (e) its terminal 

 sensory filaments, (f) the cascum of stomach, (g) optic 

 ganglion, (h) stomach, (i) oesophagus, (j) the muscles 

 which move the eye, also part of the labrum. 



Fig. 4. antennae of same. 



Fig. 5. ephippium of M. rectirostris. 



Fig. 6. " of M. paradoxa. 



Fig, 7. seminal cell of M. paradoxa ; 7a, a group less magnified. 



Fig. 8. seminal cells of M. rectitvstris. 



Fig. 9. first foot of male of M. paradoxa. 



Fig. 10. " " " " '■ ;i^, rectirostris (from Weismann), 



Fig. 11. male M. rectirostris (from Weismann). 



Fig. 12. head of Ceriodaphnia rotunda. ( This and the following 

 numbers after P. E. Mueller.) 



Fig, 13. head of C. pimctata. 



Fig. li. " C. pulchella. 



Fig. 15. " C. reticulata. 



Fig, 16. " C. quadraufjula. 



Fig. 17. " C. quadrangida. 



Fig, 18. post-abdomen of C. quadrangida. 



Fig. 19. '' C. pulchella. 



Fig. 20. " C. megops. 



Fig. 21. " C. reticulata. 



Fig. 22. " C. laticaudata. 



Fig. 23. " C. rotunda. 



