BAD MARY T. HARMAN 
he does not state definitely how long a time a single observation 
was extended, evidently it extended over a much longer time 
than mine, for he says: 
I am under the impression that cells which are cultured in this way 
do not undergo cell-division at all. JI made charts of my slides which 
I had under observation for a week at a time and checked the behavior 
of all the cells in each slide with camera lucida drawings, comparing 
those made one day with those made on the day previous. If any 
increase in number of cells had occurred, I should have noticed it, of 
course. 
Since the cells in Morse’s experiments behaved in every way 
similar to the cells in my experiments, the comparatively short 
time that my experiments were under observation can make no 
difference. The only conclusion that can. be drawn is that, 
~ under the conditions of the experiment, the nuclei do not divide. 
OBSERVATIONS 
Observations have been made upon the spermatogonial divi- 
sions and spermatogenesis, oogonial divisions, synapsis and the 
growth period, maturation divisions, and the cleavages. More 
attention has been given to the cleavages because it is here that. 
the character of cell-division is most uncertain. 
1. Spermatogonial divisions and spermatogenesis 
My observations on the spermatogonial cells show nothing 
that I can in any way interpret as amitosis. It is true that I 
find few cells which are in the characteristic stages of mitosis. 
Most of the spermatogonial cells are in the so-called resting 
stage. I find no constricting nuclei and no cells which contain 
nuclei in contact. In early post synapsis the chromatin assumes 
the form of a more or less connected spireme, usually in contact 
with a large nucleolus which lies to one side of the nucleus (fig. 
A, plate 1). A group of cells in the anaphase of the first spermat- 
ocyte division is shown in figure B. The spindle fibers are very 
delicate, and, at the poles, there are small but very distinct, 
deeply staining centrosomes. No aster and no definite cell-wall 
is distinguishable. The second spermatocyte division follows 
