160 
SYDNEY HICKSON AND ,T. T. WADSWORTH. 
mitosis shown in fig. 2o. In this stage the chromatin 
grannies are arranged in lines running from the poles towards 
the equator, but there is a clear zone free from chromatin 
running through the equatorial belt. The three examples of 
micronuclei in this stage we have found measured 6’8 /u 
by 6'3 ft, 8'o fi by 5'6 and 6'8ju by 5'7 /u respectively. 
They are oval or nearly spherical in shape. Being small and 
less pointed than the examples we have seen of the stage 
shown in fig. 26 it might be supposed that they come eai’lier 
in the mitosis. On the other hand, the separation of the 
cln-omosomes leaving a clear zone in the equator suggests 
that the metaphase has begun. If this is the correct inter- 
pretation of them then it seems probable that the onset of 
the metaphase is accompanied by a contraction of the 
figure. 
In the next stage the chromatin gi’anules are collected in 
two groups at the poles of the figure, which is 14'5 ju hy 4 /u in 
size (fig. 27). In the broad band connecting these poles 
definite plastin lines can be distinctly seen. In the next 
stage we have observed the poles are further apart, the total 
length of the figure being 20‘4 /t (fig. 28). The poles ai’e 
.5'1 fi in diameter and contain an immense number of evenly 
scattered minute chromatin granules, but we have not been 
able to discern any plastin network connecting them. The 
band connecting the two poles has shrunk in the middle to 
3‘5 fi in diameter. The same plastin lines may be seen in 
this band as in the last stage. In the final stage (fig. 29) 
the chromatin grannies are more concentrated towards the 
inner hemisphere of each pole and there is an appearance of 
a “ pole-plate” similar to that of Paramecium. The spindle 
is much narrower. Our examples of this stage are smaller 
than those of the last named, the measurements of the example 
figured being — total length 15'6ju, diameter of the poles 
3'4/j, diameter of the spindle P7 /i. 
The history of the division of the micronuclei of Dendro- 
soma that we have just described is different in many res- 
pects from that we described in Dendrocometes in 1902 ; but 
