250 T. H. Morgan 
H-K). The accessory chromosomes now begin to contract and 
clearly move towards one pole, always to that lying in the larger 
cell. At the same time the chromosomes at the opposite pole fuse 
or stick together, and the surrounding cytoplasm, retreating to the 
e@ ry oe 
& e e.@ & ee 
“fo ee Sek. fT) 
RB i: D E 
0,¢ @e° 
06 
be atonnies 
F G H 
ee ee 
®»9 
r) M N O 
~ 
terse 
“GD 
GR) 
= CM) 
P =. 
Fig. VI Spermatogenesis: A-C, equatorial plates of first spermatocytes; D-I, dividing first 
spermatocytes; K-M, after division; N-Q, equatorial plates of second spermatocytes; Q-U, dividing 
second spermatocytes. 
larger cell (as the constriction passes down), there is produced a 
small cell containing four fused chromosomes, and a large cell con- 
taining six, i.e., four separate chromosomes and the two accessories. 
A nuclear space has appeared around the four chromosomes in the 
