The Spermatogenesis in Pentatoma up to the Formation of the Spermatid. gg 



Explanation of the Figures. 



Plates 1—5. 



All the figures, except 225, represent elements of one testicle of Pen- 

 tatoma, which had been fixed in Hermann's fluid and stained by Hermann's 

 saifranine-gentian violet method. All outlines are drawn with the aid 

 of the camera lucida. With the exception of Figs. 225 — 227, all are 

 represented under the magnification afforded by a Zeiss microscope, 

 with a tube length of 180 mm, ocular 4, and the homogeneous im- 

 mersion lens Vi2j ^^ seen at the height of the microscope stage. In 

 the plates all numbers marked with an asterisk denote cells of the 

 largo generation. As far as possible the sequence of the figures shows 

 the sequence of the stages. The following abbreviations have been 

 employed : 



c centrosome Cy. P cytoplasm 



c (Is centrosomal centrodesmosis Id. Z idiozome 



Chr chromatin L linin 



Chrs chromosome M. F mantle fibres 



C. Mb cell membrane n true nucleolus 



Cw. i^ connective fibre n. 2 chromatin nucleolus 



Cn. T connective tissue N. Mb nuclear membrane 



C. sp. 1 primary central spindle P. F pole fibres 



c. sp. 2 secondary „ „ Y early yolk substance 



c. sp. 3 tertiary „ „ Yk. Gl mature yolk globules. 



Plate 1. 



. Fig. 1. Rosette of large spermatogonia in the rest stage. 

 Figs. 2 — 4. Spermatogonia in the rest stage. 



Fig. 5. Rosette of spermatogonia in the early stages of the pro- 

 phase of mitosis. 



Figs. 6 — 10. Spermatogonia, dense spirem stages. 



Fig. 11. Rosette of spermatogonia in various spirem stages. 



Figs. 12, 13. Spermatogonia, loose spirem stage. 



