404 LOUIS MAX HICKERNELL. 



PLATE IV. 



FIG. 13. Frontal section through middle of contracted P. roseola, not dried. 

 Zeiss Oc. 6, Obj. 2 mm. 



FIG. 14. Slightly oblique section through a contracted animal, not dried. 

 Leitz Oc. 4, Obj. 2 mm. 



FIG. 15. Frontal section through middle of a rotifer recovering from desic- 

 cation. Animal was killed four hours subsequent to the addition of water. Zeiss 

 Oc. 6, Obj. 2 mm. 



FIG. 16. Frontal section through rotifer kept in an evacuated calcium chloride 

 desiccator for eighteen days previous to fixation. Leitz Oc. 4, Obj. 2 mm. 



FIG. 17. Section of foot-gland cells of a rotifer which was kept in an evacuated 

 desiccator for fourteen days previous to time of fixation. Leitz. Oc. 12, Obj. 2 mm. 



FIG. i8a. Section of foot-gland cells of a normal active animal. Leitz Oc. 12, 

 Obj. 2 mm. 



FIG. 1 86. Section of foot-gland cells of an animal kept for fourteen days in 

 an evacuated desiccator and then placed in water for one and one-fourth hours 

 previous to fixation. Leitz Oc. 12, Obj. 2 mm. 



FIG. 19. Section of foot-gland cells from animal dried one week at room 

 temperature. Zeiss Oc. 6, Obj. 2 mm. 



FIG. 20. Section of vitellarium from animal dried five days at room tempera- 

 ture, placed in water four hours, then killed and sectioned. 



