124 
Arlow Burdette Stout 
tened. They are often elongated in the direction of their alignment 
in the spireni. 
Imraediately after diakinesis the continuity of the bivalent discrete 
sphem beconies stUl more conspicuons. At first it is variously twisted 
abont in the periphery of the nucleus (fig. 25). Wlien two sister chromo- 
somes lie in the plane of the section the pahed condition is evident, ^^^len 
this Position is taken by several successive pairs the double spirem ean 
be traced without difficiüty, especially if the pairs are rather dose together. 
The spirem is, of course, so twisted that in the sections one of a pair of 
chromosomes frequently lies below the other and then the pah, except 
on careful focussing, may appear as one mass. 
The important fact that caii be established in Carex is that foUow- 
ing the post-synaptic spirem the chromosomes reappear as oval bodies 
cxactly comparable in size, shape, and number with those of the somatic 
prophases in the root tip and that these chromosomes here also have 
a definite serial arrangement. The only difference between this spirem 
and the vegetative spirem is that here the seriaUy arranged nnits are 
double. 
Early in diakinesis cytoplasmic changes preparatory to the forma- 
tion of the heterotypic spindle may be seen. At first there is an accu- 
mulation of semi-fibrillar material abont the nucleus. From this there 
develops a felted zone of rather short fibres which gradually become 
more conspicuons and form a weakly developed multipolar spindle. The 
multipolar stage is, however, not sharply marked and soon changes to a 
broad-poled spindle precisely like that of the somatic divisions. 
The spindle fibres in all divisions stahl readily and the entire spindle 
figure is conspicuons. Whüe all stages of the early development of the 
spindle outside of the nucleus can be easily traced, I have not observed 
any definite intra-nuclear fibres such as have been noted in certain flower- 
ing plants especially by Allen (1903 and 1905) for Larix and Lilium. 
I find no evidence as to the nature of the intra-nuclear mechanisni which 
operates previous to the breaking down of the nuclear membrane. In the 
prophases of the somatic divisions the chromosomes draw away from the 
membrane, the spirem becomes centrally aggregated and then loosens 
somewhat before the nuclear membrane breaks down and the vüsible 
spindle fibres grow into the nuclear cavity. In the heterotyiiic prophases 
still more complicated processes occur. After diakinesis, however, the 
double spirem behaves similarly to the single spireni of somatic divisions. 
It is noticeable that in all resting nuclei the chromosomes are de- 
cidedly peripheral. They lie against the nuclear membrane. In the 
