•98 MARGARET LEWIS NICKERSON. 



EXPLANATION OF PLATE XXXV. 



Fig. 15. Section through glandular organ of second type showing the intra- 

 cellular sacks with their communicating ducts. X 620. 



Fig. 16. Section through glandular organ of second type showing appearance 

 of cell contents. The plane of section was not such as to show connection of 

 intracellular sacks. X 575. 



Fig. 17. Section through glandular organ of second type to show late condi- 

 tion of enlarged sacks. Cell contents shown only on left, x about 550. 



Fig. 18. Optical section of bulb belonging to second type of non-glandular 

 organ. Drawn from living tissue, x 250. 



Fig. 19. Section through glandular organ of second type representing early 

 phase of activity, x 550. 



Fig. 20. Section through glandular organ of first type showing two nerve 

 nuclei at base, x 575. 



Fig. 21. Portion of section of Phascolosoma Gouldii in region of retracted 

 proboscis to show arrangement of epidermal organs. X ■T^y 



Fig. 22. Section through glandiilar organ of first type showing cells in various 

 stages of activity. 



