322 TAKU KOMAI 
evidence for it derived from his study of the spermatogenesis 
of Cambarus and Cancer seems to be fairly convincing. Like- 
wise, in the present material I was able to trace fairly well the 
successive changes of chromatin threads from the leptotene to 
the pachytene stage, and, notwithstanding that my observation 
is regrettably imperfect as to the important phenomenon of the 
tetrad formation, there seems to be hardly any room for doubt- 
ing the existence of parasynapsis for the present case. 
b. Comparative study of spermatozoa of the Decapoda and the 
Stomatopoda 
As has already been mentioned, Nichols (09) has pointed 
out that the spermatozoon of Squilla ‘‘seems to forecast the 
spermatozoon of the Decapoda.” It is true that the sperma- 
tozoon shows at first glance a marked resemblance to that com- 
monly found in the Decapoda, especially in forms belongin to 
the group Reptantia. However, to decide the question how 
; : ee 
far this apparent resemblance has to do with affinity in a real 
morphological sense, a more careful study is necessary. On the 
morphology and development of the decapod spermatozoa much 
is known through works of Grobben (’78, ’06), Gilson (’86), 
Brandes (’97), Labbé (’03, ’04), Koltzoff (03, ’06), Andrews 
(04), Nichols (09), Retzius (’09), Binford (13), Reinhard (713), 
and Fasten (714, 718). An excellent review of the literature 
-occurs in Fasten’s earlier work (14). 
The above resemblance is mainly due to the fact that the 
sperm tail is replaced by a cytoplasmic vesicle which gives the 
entire spermatozoon an appearance radically distinct from the 
ordinary filiform ones. The vesicle arises in both spermatozoa 
from a vacuole appearing in cytoplasm and enlarges to occupy 
by far the greater part of it. Thus far the vesicles occurring 
in the two kinds of spermatozoa are in agreement. In the 
decapod spermatozoa the vesicle contains a substance staining 
rather deeply with various dyes and, according to Koltzoff (03, 
06) and Reinhard (’13), it arises by the accumulation of a 
kind of granule called by them ‘Kapsel- or Schwanzkérnchen.’ 
