110 XICHOLS— SPERMAT0EGXESI3 ONISCL^rf ASELLUS LIXN. [April , 



Plate 

 XV 



Plate 

 XVI 



Plate 

 XVII 



f 32> *33-47- Prophases of the first spermatocyte. 44. 1-16, chromo 



somes. 

 46 and 47. Strongly decolorized sections showing the longitudinal 



split of the chromosomes. Divergence of the centrosomes. 

 48. {a) Side view of the equatorial plate of the first spermatocyte. 



{b) Anaphase of the first spermatocyte. 

 49-53. Equatorial plate of the first spermatocyte in side view. 

 54. Chromosomes of the first spermatocyte, showing the longitudinal 



split. 

 55,56. Pole views of the equatorial plate of the first spermatocyte. 

 57. Slightly oblique view of the same. 



58. 



59. 

 60. 

 61. 

 62. 



63. 

 64. 

 65. 

 66, 

 68. 



69, 

 70. 



71. 



72. 



73- 



Anaphase (side view). 

 Anaphase (pole view). 

 Anaphase (tangential sections). 

 Telophases. 



Side view of the equatorial plate of the second spermatocyte. 

 The same more strongly decolorized. 

 Pole view of the same. 

 Metaphase. 

 67. Telophases. 



{a and b') Mode of formation of the two main types of chromo- 

 some in the first spermatocyte, {c) Intermediate form. 

 70. Reconstruction of the nucleus of the spermatid. 

 Disappearance of the cell boundaries, x, remains of degenerated 

 cells. 



Variation in the appearance of the spermatid nucleus. 

 Commencing elongation of the spermatid nucleus. 

 Group of spermatids from near the margin of the testis lobe. Ap- 

 pearance of cytoplasmic striaticns (hematoxylin and Bordeaux 

 red). 

 79. Further development of the spermatids. 



Stage succeeding 72. (<?) Longitudinal; {b) transverse section 

 (iron hematoxylin). 



Longitudinal section (iron hematoxylin). 



Longitudinal section (Biondi-Ehrlich). The middle figure alone 

 is complete anteriorly. 



{a) Longitudinal; (i^) oblique section (iron hematoxylin). 

 79, Nearly malura sperm colonies in incomplete longitudinal sec- 

 tion (hematoxylin and Bordeaux red). 



Cross sections at different levels of nearly mature sperm colonies. 

 {a) anterior to the nuclear region ; (^b, c and d') nuclear region ; 

 ((?), posterior to nuclear region (saffranin and malachite green, 

 black ■=^ red, gray r=r green). 



