168 CANNON: STUDIES. IN PLANT Hysrips 
a sharp angle to the spindle, well into the cytoplasm, and make 
up the fibrillar layer which is so conspicuous in the cells. Those 
of the fibers that are in the immediate neighborhood of the daugh- 
ter nuclei soon lose the filar appearance, become structureless 
and the chromosomes in early telophase lie freely in an apparently 
homogeneous substance. 
The reconstructed nuclei possess a distinct nuclear wall, the 
chromatin forms a coarse reticulum (f. 72) and the nucleolus is 
reconstructed. The steps in the reformation of the daughter 
nuclei were not closely observed but appeared roughly to corre- 
spond to the reverse of the breaking down of the mother nucleus. 
When the daughter nuclei are fully reconstituted the fibers of 
the achromatic figure may still be seen in the inter-nuclear cyto- 
plasm ; they persist during the division of the nuclei and even may 
be observed in the cytoplasm of the young tetrad. The presence 
of these spindle-fibers in normal mitoses, and the total absence of 
them in abnormal ones, form a reliable basis for judging whether 
the mitosis was normal or abnormal, but this of course would 
probably not be true if the divisions were so nearly normal as 
some described by Juel, Guyer and Metcalf. Such, however, are 
not to be found in the cotton hybrid. 
The daughter nuclei are so small that it is difficult to study at 
all closely the sequence of changes which lead up to and accom- 
pany their division, and, therefore, I contented myself with observ- 
ing certain definitive phases only. 
Continuous, contractile and mantle fibers are of course present 
in the achromatic figure, but the latter do not eventually form a 
fibrillar layer in the cytoplasm as the mantle fibers of the preced- 
ing division do. The continuous fibers persist and may be seen 
along with those from the first division in the young tetrad. 
In the prophases of this division the chromatin masses arrange 
themselves in a nuclear plate as in the former division, but there 
is a distinct difference between the chromatin of the first and of the 
second mitosis. In the prophases of the second mitosis the chro- 
mosomes are of a uniform size and appearance and are rod-shaped. 
I was not able to make out the presence of the second and pre- 
cocious split which in some forms may be observed at this time. 
In the metaphase each chromosome divides into two equal por- 
