758 THOS. H. MONTGOMERY, JR. 
(D,d, fig. 101, polar view), there composing a bivalent body that 
divides reductionally in that the larger idiochromosome goes into 
one spermatid and the smaller into the other (D,d, figs. 102, 103). 
Polar views of the anaphase of this second maturation division 
show, accordingly, the smaller idiochromosome in one sperma- 
tid and the larger in the other (figs. 105, 106). 
In each spermatid the idiochromosome comes to lie in the 
nuclear vacuole apart from the autosomes, and differs from them 
by its more rounded form (D,d, fig. 110). The idiochromosome 
of each spermatid nucleus continues central (figs. 111-116), 
while the autosomes assume a peripheral position.2 The idio- 
chromosomes become connected with fine threads and chains of 
minute globules. Later they become much more irregular in 
form (D, figs. 117-127); each generally seems like an irregular 
rod, but often as two or three separate portions that may be sec- 
tions of such a rod. In one case an idiochromosome had the 
appearance of a ring surrounding a granule (fig. 124). During 
this period also they lose their affinity for nuclear stains and 
appear pale. The nuclear contents appear highly variable, but 
the idiochromosome may always be distinguished from the 
threads and minute globules as well as from the peripheral chro- 
matin. 
Then follows the sudden disappearance of the idiochromosome. 
It first approaches the centriolar pole of the nucleus, as seen 
in figs. 126, 128 to 180. Then the autosome envelope of the 
nucleus opens widely at that pole and the nucleus undergoes a 
marked shrinkage in size (figs. 180 to 135). It is rarely that one 
finds the condition of figs. 1381 and 132 with nuclear material 
evident in its outward passage, from which I judge the process 
must take place very rapidly. It is also rare to find any trace 
of exuded nuclear material within the cytoplasm (figs. 131-134) 
though I have sought for it with a variety of staining methods. 
It is to be noted, however, that immediately following this stage 
® From the stage of fig. 115 on I have marked the idiochromosome by the capital 
letter D, though in these later stages it seems impossible to say for a particular 
nucleus whether it is the larger or the smaller. 
