92 ILUNOIS BIOLOGICAL MONOGRAPHS [286 



EXPLANATION OF PLATE 



Fig. 25. — Reproductive organs of DdyeUia megacephala; X about 200. 



Fig. 26. — Protonephridiiun of DalyeUia alba; X about 340. 



Fig. 27. — Rhabdites of Typhloplana viridaia, one in cell. Camera ludda; X 350. 



Fig. 28. — ^Eyes of Strongylostoma rosaceum; X about 200. 



c. Lateral surface of eye; X about 200. 

 Fig. 29. — ^Tail region of Mesostoma angulare; X about 100. 

 Fig. 30. — Rhabdites of Typhloplana viridata. Camera ludda; X 350. 

 Fig. 31. — Rhabdites of Typhloplana viridata, old cell; X about 300. 

 Fig. 32. — ^Tail region, Mesostoma simplex; X about 100. 

 Fig. 33. — Rhabdites in cell, Mesostoma simplex. Camera ludda; X 150. 

 Fig. 34. — Mesostoma simplex, vitelline gland cell, showing stored oil globules; X about 250. 

 Fig. 35. — Ovary of Mesostoma simple f; X about 350. 

 Rg. 36. — Cirrus sac, Mesostoma simplex; X about 350. 

 Fig. 37. — ^Testis, Mesostoma simplex; X about 350. 

 Fig. 38. — Rhabdites in cell, Mesostoma simplex; X about 200. 

 Fig. 39. — ^Eye, Dalyellia megacephala; X about 175. 

 Fig. 40. — ^End view of rhabdite-bearing cell of Mesostoma simplex; X about 350. 



