EXPLANATION OF FIGURES 



All figures were outlined with a Zeiss camera-lucida, at the level of the stage 

 of the microscope. Lens used: Zeiss apochr. imm. 1 m.m., 5; ocular 12. Arti- 

 ficial light (gas). 



PLATE 1 



EXPLANATIOX OF FIGURES 



1 Fundulus majalis. Fixation: Benda, without acetic acid. Stain: Benda. 

 Epithelium of an excretory duct. 



2 Fundulus heteroclitus. Fixation: Benda. Stain: Benda. Supptised in- 

 terstitial cells. 



3 Fundulus majalis. Fixation: Benda, without acetic acid. Stain: Benda. 

 Group of primary and secondary spermatogonia. 



150 



