DEGENERATE (APYRENE) SPERM-FORMATION OF MOTHS. 479 
The final linking up of all the occurrences in the sperm-cell 
and their proper consummation depends on the correct 
attraction between centrosome and nucleus at the time when 
the various cell elements become formed up in line pre- 
paratory to the elongation of the spermatid. 
The growth of the sperm tail in length depends, I believe, 
absolutely on the head centrosome. Now the centrosome also 
is intimately connected with the macromitosome (nebenkern 
of some authors), at least in the later stages, when the elon- 
gation is taking place, and in the moths the centrosome is 
certainly connected with one end of the mitochondrial 
spireme. Yet we know quite well that in cellular division 
the astral rays are certainly not connected with either single 
mitochondria or groups of mitochondria. It therefore seems 
that a new relationship betwixt centrosome and mitochondria 
is brought about in later stages of sperm-formation. The 
curious and definite groupings of mitochondria around the 
filament in such a case as Enteroxenos might possibly be 
otherwise accounted for, but I believe the centrosome to be 
mainly responsible. The acroblast also offers curiously con- 
tradictory evidence; it undoubtedly (in moths, at least) 
becomes definitely oriented towards the nucleus in several 
stages of spermatogenesis, and yet in mitosis it keeps appa- 
rently completely within the zone of the astral rays, near the 
centrosomes. From the maturation divisions and subsequent 
spermiogenesis I conclude that the following inter-relation- 
ships could be demonstrated between — 
(1) Nucleus and acroblasts. 
(2) Acroblasts and centrosomes (in cell division alone). 
(3) Mitochondria and centrosome only in later stages (after 
spireme formation). 
(4) Centrosome and nucleus (not chromosomes) only in 
later stages, when both bodies become adherent one to the 
other. (I do not here refer to division of the cell.) 
The question of the relationship of mitochondria to other 
cell elements in cell division I believe to be settled by some 
stages, especially in the prophases, where in moths the seed- 
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