324 TAKU KOMAI 
lying more apart from the nucleus. In the decapod sperma- 
tozoa, on the other hand, the centrosome undergoing transfor- 
mation is invariably the distal one and that which does not, the 
proximal centrosome. In short, the resemblances of the sper- 
matozoa of the two groups, striking as they are at first glance, 
seem in large measure to be of a rather superficial nature than 
of a strict morphological significance. 
It may be added that a case somewhat suggesting the change 
of the proximal centrosome in the Squilla spermatozoon is 
afforded by the spermatogenesis of Gammarus (Késter, ’09, 
10). According to the accounts of that author, the proximal 
centrosome placed at the base of the sperm head sends out a 
fiber through the head toward the perforatorium and becomes 
united with the latter. 
SUMMARY 
1. In the testicular tube the seminal cells are arranged in two 
or three sharply defined zones. 
2. Among the spermatogonial cells two kinds may be distin- 
guished, namely, the primary and the secondary. 
3. The nutritive cells probably have a common origin with 
the spermatogonial cells. The view that the latter may be 
transformed from the former seems to be erroneous. 
4. The number of chromosomes appearing during spermato- 
gonial divisions is forty-eight. 
5. After the last spermatogonial mitosis the chromatin mate- 
rial is diffused into the nuclear cavity; the leptotene threads 
make their appearance from this uniform ground; they are 
separate from the beginning. 
6. In the synizesis stage the chromatin threads aggregate 
together in the central region of the nucleus. 
7. In the synapsis stage the chromatin threads fuse in parallel 
fashion, or, in other words, the fusion is carried out parasynap- 
tically. 
8. Through each pachytene thread a longitudinal split is 
distinctly discernible and the threads show a clear bouquet-like 
arrangement. 
