66 Wisconsin Academy of Sciences, Arts, ancl Letters. 
considerable time, after which the membrane and the: nucleole 
disappear. The network contracts and collects into two very 
long and irregular chromosomes, which, they think, split longi¬ 
tudinally, though they have not seen the process very fully. 
The two halves of the chromosomes immediately separate and 
in passing to the poles become shortened and very irregularly 
thickened. The daughter nuclei are then constructed at the 
poles. As will be seen, the figures described further on differ 
widely from those given by these authors. 
Poirault and Raciborski (3) do not regard the fusion of nu¬ 
clei in the teleutospore as directly comparable: to the fusion of 
differentiated male and female nuclei. Later Raciborski (5) 
has suggested that it is similar to the delayed fusion in 
the zygospore of Basidiobolus ranarum and proposes the term 
zeugite for all such cells in which occurs a fusion of nuclei be¬ 
longing to the same cytoplasmic mass. 
Juel ( 6) has more recently studied the division of the fusion 
nucleus of Goleosporium campamdae. His figures of the nu¬ 
clear division differ widely from those of Poirault and Racibor¬ 
ski and Sappin-Trouffy. The figures which he shows are very 
much like those in other fungi and algae. Instead of the axis 
of colorless substance of Sappin-Trouffy he finds a red staining 
spindle. At each pole he finds a small rounded red or violet 
stained mass which sends out into the surrounding cytoplasm 
delicate thread like processes, so that there is here formed a 
characteristic polar aster. The chromatin lies in the equatorial 
region as a finely granular or fire thready mass. Individ¬ 
ual chromosomes could not be distinguished. Later the spindle 
body becomes drawn out; and thinner in the middle. The chro¬ 
matin mass becomes constricted in the middle and then sepa¬ 
rates and passes to the poles. The structure about the poles 
remains unchanged. 
The exceptional character of the karyokinetic figures as rep¬ 
resented by Poirault and Raciborski, as well as by Sap¬ 
pin-Trouffy, suggests the: necessity for further investigation of 
nuclear division in the rusts, and we have undertaken a more 
detailed study of a single form as promising the best results. 
A cursory examination of some seventeen species of Puccinia, 
