90 ILLINOIS BIOLOGICAL MONOGRAPHS [284 



EXPLANATION OF PLATE 



(Figures 1 to 9 represent Slrongylosloma rosaceum) 

 Fig. 1. — Reproductive organs, lateral view; X about 150. 

 Fig. 2. — Reproductive organs, dorsal view; X about 150. 

 Fig. 3.— Cyclops shell with worms feeding within; X about 10. 

 Fig. 4. — Ovary, camera lucida; X 67. 

 Fig. 5.— Testes; X about 67. 



Fig. 6. — Rhabdites lying free, camera lucida; X 50. 

 Fig. 7. — Diagram of worm extended; X about 60. 

 Fig. 8. — Diagram of worm contracted; X about 60. 

 Fig. 9. — Cell with rhabdites, camera lucida; X 50. 



(Figures 10 to 20 were drawn with camera lucida and show eggs of 

 Slrongylosloma rosaceum in various stages) 



Fig. 10. — Egg in one-cell stage; X 67. 



Fig. 11.— Eight-cell stage; X 67. 



Fig. 12.— About thirty-two-cell stage; X 67. 



Fig. 13. — Gastrula nearly complete; X 67. 



Fig. 14.— About fifth day; X 67. 



Fig. 15. — At 9:56 a.m. in process of turning; X 67. 



Fig. 16.— At 10:08 a.m. rotated 180°; X 67. 



Fig. 17. — Seventh day, much folded; X 67. 



Fig. 18. — Eighth day, dorsal view; X 67. ] 



Fig. 19. — Eighth day, lateral view; X 67. 



Fig. 20. — ^Ninth day, empty shell; X 67. 



Fig. 21. — Macrostoma album, sHghtly compressed; X about 50. 

 Fig. 22. — Typhloplana viridata, sHghtly compressed; X about 80. 

 Fig. 23. — Dalyellia megacephala, slightly compressed; X about 27. 

 Fig. 24. — Dalyellia alba, sUghtly compressed; X about 40. 



