94 ILUNOIS BIOLOGICAL MONOGRAPHS {288 



EXPLANATION OF PLATE 



Fig. 41. — Mesostoma angular e, lateral view, slightly compressed; X 35. 



Fig. 42. — Mesostoma simplex, slightly compressed; X 26. 



Fig. 43. — ^Eyes of Planaria mactdata; X about 67. 



Fig. 44. — Eyes of Planaria maculaia, camera ludda; X 67. 



Fig. 45. — ^Uterus of Mesostoma angular e, showing yoimg worms and eggs just ready to hatch. 



X about 35. 

 Fig. 46. — Section thru fission plane of Stenostoma giganteum. Camera ludda; X 50. 

 Fig. 47. — Stenostoma glandiferum, dorsal view, slightly compressed; X about 90. 

 Fig. 48. — Stenostoma giganteum, lateral view sUghtly compressed; X 60. 

 Fig. 49. — ^Head of Dalydlia dodgei, antero-dorsal view, showing elevated mouth; X about 70. 

 Fig. 50. — ^Head of Stenostoma leucops, phar>Tix closed; X about 67. 

 Fig. 51. — ^Head of Stenostoma leucops, pharynx open; X about 67. 

 Fig. 52. — ^Nematoc>'St of Microstoma caudatum; X about 850. 

 Fig. 53. — ^Lateral view of head of Microstoma caudatunr, X about 67, 

 Fig. 54. — Strongylostoma rosaceum, lateral view, slightly compressed; X about 50. 

 Fig. 55. — ^Transverse section, Mesostoma angular e, showing folds of body walL Camera 



ludda; X 170. 

 Fig. 56. — ^Ventral view of head of Microstoma caudatum; X about 67. 



