196 J. DUESBERG. 



EXPLANATION OF PLATES. 



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

 the microscope. Lenses used: for Figs. 1-12, Zeiss apochr. immers. 2 mm. (ap. I, 

 40), in combination with ocular 12; for Fig. 13, Zeiss apochr. imm. i mm. 5 (ap. 

 I, 30), and ocular 6. Artificial light (gas). 



EXPLANATION OF PLATE I. 



1. Interstitial cell with idiosome and 2 centrioles. Fixation and stain after 

 Benda. 



2. Interstitial cell with two nuclei, idiosome and 4 centrioles. Fixation and 

 stain after Benda. 



3. The apparatus of Golgi. Ramon y Cajal's method. Counterstain: Ehrlich's 

 hematoxylin. 



4. Another form of the apparatus of Golgi. Ramon y Cajal's method. Counter- 

 stain: methylgreen. 



5. Interstitial cells with several crystals of the thin type. Fixation and stain 

 after Benda. 



6. A crystal of the thick type. Fixation and stain after Benda. The same eel 

 shows part of the network made up of modified chondriosomes. 



