Davis.— Spermatogenesis. 
PLATE 4. 
All figures magnified 966 diameters. 
Figs. 57-63. Dissostetra carolina. 
Fias. 57, 58. Stage g, primary spermatocyte. The loop-shaped monosome 
is shown in both eases. 
Fiaes. 59-60. Stage h, primary spermatocytes. The tetrads are already 
Fia. 
Fic. 
Fig. 
Fig. 
LD te 
Fia. 
Fig. 
Fic. 
66. 
67. 
68. 
formed. The rod-shaped monosome is seen in each cell. The 
irregular deeply staining body in the upper part of the nucleus 
in Figure 59 is a plasmosome. 
Stage i, primary spermatocyte. The monosome is seen at the 
right applied to the nuclear membrane. 
Late prophase of first maturation division. 
. Metaphase of first maturation division. The rough rod-shaped 
element lying at an angle to the spindle axis is the monosome. 
Metaphase, first division of Arphia tenebrosa. A monosome lies 
near each spindle pole. 
Figs. 65-68. Dvissosteira carolina. 
Early anaphase of first division. The monosome lies near the left 
spindle pole. 
Late anaphase of first division. 
Group of cells from the distal end of the follicle. The apical cell 
is seen below and at the right —- the one nearest the numerals ‘‘67.” 
Surrounding the apical cell above and at the left are three pri- 
mary spermatogonia in different stages. Above and at the left 
of the primary spermatogonia are four connective-tissue cells. 
Young spermatocyst from near distal end of follicle. Several con- 
nective-tissue cells surround the spermatogonia. 
