12G 
Arlow Burdette Stout 
in the early stages of tlie equatorial plate the series of double chromo- 
somes can be traced throughout most of its length. The spirem is raore 
or less tvvisted so tliat one chromosome of a pair inay lie above the other. 
As the metaphase stage approaches the spirem is so oriented that when 
viewed froni the poles all of the pairs lie in this position. Juel’s figure 
of this stage for Carex acuta shows fifty-two chromatin bodies, but it is 
not clear that they are bivalent (Juel, 1900, plate XVI, figure 32). 
Juel’s figures show a Suggestion of the serial arrangement of the chromo- 
somes. His failure to discover the bivalence of the chromosomes in 
diakinesis and in the equatorial plate was perhaps due to the fact that 
he did not make a eomparative study of the somatic divisions. 
A lateral view of the heterotypic division figure is shown in figure 28. 
The homologous chromosomes are about to separate. This stage is 
similar in general appearance to the early metaphase of a somatic di\'i- 
sion; but there are, of course, but one half the number of chromosomes 
in each of the two spirems as they separate and they are here twice as 
large as the daughter chromosomes of the somatic metaphase. The 
chromosomes part almost simultaneously throughout the spirem and 
appear in lateral view in two well ordered ranks. They do not show a 
split or line of Separation for the formation of the daughter chromosomes 
of the homoeotypic division; this may be due to staining or fixation, 
though I am inclined to believe from the appearance that the split does 
not occur at this stage, or that if it does occur, the two halves reniain 
closely joined together. 
For a time during the early anaphases the chromosomes are readily 
identified and the serial arrangement is more or less in evidence in the 
])olar view. As the poles are reached the chromosomes are loosely massed 
together so that in early tclophases there is an aggregation of the indivi- 
duals. A nuclear membrane soon forms, and, as the daughter nucleus 
continues to enlarge, clear spaces show between the chromosomes, a 
nucleole appears and the serial arrangement of the chromosomes is clearly 
to be observed (fig. 29). The central spindle which was strongly deve- 
loped during the early anaphases does not produce any pronounced cell 
plate. This spindle has largely disappeared when the sister nuclei are 
completely reorganized. 
The Homoeotypic Division. 
The two sister nuclei reach a completely resting condition, but soon 
enter on the prophases of the second division. The chromosomes are 
evidently full-sized throughout this ])eriod. At least there is no period 
