152 RAYMOND BINFORD 
spermatozoa out of the tubule. This process is not completed, 
however, before a third batch is formed or even a fourth started. 
Spermatogonial mitoses 
In the resting spermatogonial nucleus the chromatin is arranged 
in a loose net-work with enlargements at various places (fig. 5). 
This net, for the most part, lies just inside the nuclear mem- 
brane, the central part of the nucleus containing almost no stain- 
ing material. The behavior of the chromatin during the pro- 
phase of mitosis is as follows: the knots of chromatin become 
enlarged and more regular in outline while the connecting threads 
become smaller and disappear. The chromatin finally assumes 
the form of a large number of paired spheres (fig. 6). An effort 
was made to count these spheres and numbers were obtained 
as follows: 51, 55, 57, 58, 62, 62, 68 and 80. One may not, how- 
ever, place very much dependence in these numbers for some 
of the spheres are always somewhat aggregated in one or two 
places so that they can not be definitely distinguished. ‘These 
chromosomes at first lie in the outer part of the nucleus just 
inside the nuclear membrane, but are later massed in the center, 
from which condition they move to their positions in the equa- 
torial plate. Figure 7 is an optical section of the nucleus show- 
ing the peripheral arrangement of the chromosomes. In the 
metaphase and anaphase of the mitosis, the members of each 
pair are separated from each other and pass to ‘opposite poles of 
the spindle (fig. 8). These divisions of the spermatogonial nuclei 
do not occur simultaneously throughout the mass, but singly 
here and there among the nuclei. The spermatogonia become 
smaller as they become more numerous. 
Maturation mitoses 
Finally the spermatogonial divisions cease and the nuclei pre- 
pare for the reduction divisions. The quantity of chromatin 
seems to increase and the spireme makes its appearance. At 
first it is very long and slender and complexly folded all through 
the nucleus. The iron-hematoxylin stain can be controlled so 
