Opalina. 237 
Telophases. 
When the chromosomes have passed almost to the poles of the 
nucleus, they stop their migration and enter upon the changes of 
the telophase. These changes affect both the chromosomes them- 
selves and the fibrillar portion of the chromatin, as well as the 
achromatic films. The chromatin fibres in the equatorial area are 
already, or soon become, more slender and more branched. The 
fibres uniting the chromosomes to the poles of the nucleus somewhat 
more tardily undergo the same change. The longitudinal films of 
the achromatic foam similarly become less emphasized until one sees 
no distinction between the longitudinal and transverse films. The 
nucleus has now wholly lost its longitudinally striated appearance. 
Two sets of changes occur in the chromosomes, they constrict 
transversely, and they fuse. The transverse constriction of the 
chromosomes is very frequently seen during the telophases (Figs. 53, 
54, 58, Pl. XVIII). They do not all constrict transversely at this 
time for one never finds a nucleus in the condition which would thus 
result. In many cases no transverse constriction occurs until later. 
In one of the chromosomes, the first to so constrict, the division is 
very unequal, the larger moiety lying toward the equator and the 
smaller toward the pole (Figs. 53,1) 54, Pl. XVIII). The two parts 
are generally clearly seen to be united by a distinct thread resembling 
one of the thick fibres of the chromatin spindle. Another of the 
chromosomes divides more nearly equally, the slightly smaller moiety 
being toward the pole of the nucleus. As already, said this trans- 
verse constriction of the chromosomes does not always occur before 
their fusion. One cannot say which is the proper and which the 
divergent time relation between these two sets of phenomena, trans- 
verse constriction and fusion. 
The chromosomes unite by sending out thin plates of chromatin 
which pass from one chromosome to the next (Figs. 58, Pl. XVIII; 
60—63, Pl. XIX). At first perhaps but a single pair will unite 
(Fig. 58), then others will become connected. There may thus arise 
a very irregular complete ring of chromatin just beneath the nuclear 
membrane 2) (cf. O. caudata, Fig. 82, Pl. XX). This fusion may begin 
1) This figure shows the only exception I have found to the rule that the 
smaller moiety of the chromosome first to constrict lies toward the pole. In the 
posterior end of the anterior nucleus the smaller moiety of the divided chromosome 
is nearer the equator. 
2) Licger & Dusosca’s Fig. 19 is interesting in this connection (cf. Text 
Fig. IV H, page 249). 
