EXPLANATION OF PLATES, III — IV. 



155 



Fig. 12. Verson's cell (v) with surrounding small degenerating cells, taken from 

 testis of imago. Killed with Flemming's stronger solution and staintd 

 with rubin. (Leitz, Obj. 7, Oc. 4). 



Fig. 13. Verson's cell (v) with degenerating cells, taken from testis of imago after 

 copulation. Treated as above. (Leitz, obj. 7, Oc. 4). 



Fig. 14. Longitudinal section of terminal portion of ovarian tube, taken from larva 

 in third stage, (v) Verson's cell. Treated with Flemming's stronger 

 solution and stained with Flemming's saffranin solution. (Leitz, homog. 

 imm. 1/12, Oc. 3). 



Fig. 15. Testicular follicle of Papilio xuthus with Verson's cell (v). Treated as 



above. (Leitz, Obj. 7, Oc. 4). 

 Fig. 16. Testicular follicle of wild silk worm with Verson's cell (v). Treated as 



above. (Leitz, Obj. 7, Oc. 4). 



PLATE IV. 



All specimens killed with Flemming's strong solution, except those shown in 

 figs 63, 64, 82, 81 and 86. 



Fig. 17. Resting nuclei of primary germ-cells. (») nucleolus, consisting of chro- 

 matin granules. Treated with Hermann's triple staining. (Zeiss, homog. 

 imm. 1/12. Oc 4.) 



Fig. 18. Two nuclei of same stage with greater portion of cell-bodies. Treated as 



above. (Zeiss, homog. imm. i/ J2 , Oc. 5.) 

 Fig. ig. Two primary germ-cells at beginning of skein stage. Treated as above. 



(Zeiss, homog. imm. 1/12, Oc. 4). 

 Fig. 20. Five primary germ-cells, with their Nuclei at stage of segmented skein. 



In Nucleus represented at right hand side of figure chromosomes are 



much shortened. Treated as above. (Zeiss, homog. imm. 1/12, Oc. 4). 



Fig. 21. Stage of division of primary germ-cells. In left lower nucleus, seen from 

 polar view, twenty-eight chromosomes can be distinctly counted. Treated 

 as above. (Zeiss, homog. imm. r/12, Oc. 5). 



Fig. 22. Primary germ-cells of more advanced stage of division. Twenty-six, or 

 twenty-seven chromosomes are to be counted^in polar views. Treated as 

 above. (Zeiss, homog. imm. 1/12, Oc. 4). 



Figs. 23-45. Successive stages of metamorphosis of sperm-mother-cells in growing 

 stage. Figures 39, 40, 41, 42, and 43 are stained with Bohmer's hae- 

 matoxylin, and all others with Hermann's triple dyes. 



Fig. 23. Resting nuclei. These are very small in consequence of repeated divi- 

 sions in last stage. (Zeiss, homog. imm. r/12, Oc. 4). 



Fig. 24. Resting nuclei at more advanced. (Zeiss, homog. imm. 1/12, Oc. 4). 



Figs. 25 and 26. Nuclei, before skein stage. Chromatin granules are collected 

 irregularly at one side of nucleus. Nucleolus consists of small chromatic 

 bodies. (Zeiss, homog. imm. 1/12, Oc. 4). 



Fig. 27. Skein stage.. (Zeiss, homog. imm. 1/12, Oc. 4). 



Figs. 28, 28'. Granulation of chromosomes. (Zeiss, homog. imm. 1/12, Oc. 4). 



Fig. 29. More advanced stage as above. Here chromosomes are completely dest- 

 royed, (ditto). 



