SPERMIOGENESIS OF HELIX ARBUSTORUM. 
307 
the spermatocytes, in which the reduction actually took place, as sper¬ 
matogonia. 
Bolles Lee (10) gave a considerably different description of the 
division of the spermatogonia. In the spermatogonia — according to 
him — first appear 6 to 12 chromatin threads varying in length, from 
which develop 24 U-shaped chromosomes. Their ends are directed 
to a strictely determined point of the cell. The chromosomes split after¬ 
wards into two halves. The half threads are first parallel, but later 
separate, and spread in the nucleus. Bolles Lee’s figure of this last 
stage of chromatin development agrees with my Figure 3., PI. VIL, 
which stage I regard as the early spireme of the spermatogonium. The 
threads, according to Bolles Lee, afterwards become shorter and are 
then definite chromosomes. His figures of this stage are equivalent to 
my figures 5—6., PL VII. 
Bolles Lee’s statements have already been criticised by Meves (72). 
After the opinion of this latter investigator the stage, in which accor¬ 
ding to Bolles Lee the chromosomes spread in the nucleus, is equal 
to the thin spireme, which here, as everywhere, precedes the thick 
spireme, i. e. Bolles Lee changed these two stages. 
It is indubitable that Bolles Lee gave an incorrect description of 
the division of spermatogonia, because these phases which he regarded 
as those of the division of spermatogonia, do not represent the first 
phases of their division but those of the first spermatocytes. But Bolles 
Lee is certainly right when stating that the chromosomes split and 
spread through the nucleus. This stage is not the same as the thin 
spireme, as Meves believes, it is figured by Bolles Lee on Fig. 11., 
PI. I., by me on Fig. 3., PI. VII. 
2. The spermatocytes. 
The young spermatocytes are very small, never larger than the 
spermatogonia, and consist of a relatively very large nucleus and a 
small amount of cytoplasm (PI. VIL, Figs. 8—10.). The resting nucleus 
is filled by a linin network in the threads of which the chromomeres 
are suspended; we find the largest masses at the cross points. The 
primary spermatocytes always have a considerable nucleolus. It is 
unknown how long they remain in this resting stage, but till the next 
stage of development neither the cell itself grows perceptibly, nor does 
the relation of the size of nucleus and cytoplasm change. This stage is 
to be seen on Fig. IL, PL VIL, which shows a cell in the earliest phase 
of division, when the chromatin begins to arrange itself in threads, i. e. 
20 * 
