KING: CYTOLOGY OF ARAIOSPORA PULCHRA. 
221 
the cytoplasm is coarser and more vacuolate although in a few places 
it is very fine meshed. Just inside the wall is the lining plasma 
membrane which appears here to be distinctly granular. There are 
about fifty three nuclei in this oogonium, slightly more than the 
average which is about thirtv-five. Since the oogonium is already 
cut off, it is evident that anv considerable increase in this number in 
the older oogonia must be due to nuclear division. Most of the 
nuclei have already taken a peripheral position. At this stage, how¬ 
ever, there is no marked differentiation in the cytoplasm of the 
oogonium. In the Albuginaceae , observers have pointed out that, 
concomitant with and possibly causing the outward migration of 
the nuclei, there is developed in the interior of the oogonium an 
extremely finely vacuolate cytoplasm. No such differentiation has 
been seen to accompany the nuclear migration in Araiospora; when 
the nuclei have reached the periphery, the whole interior of the 
oogonium still consists of an irregular coarse and fine cytoplasmic 
mesliwork (pi. 12, fig. 11). The migrating nuclei go out and arrange 
themselves in a definite manner; instead of aggregating in groups 
at the periphery they pass out from their primary position along 
radii of the oogonium, and in this way come to be regularly distrib¬ 
uted in the region of the oogonial wall. 
As the oogonium continues to develop, the large irregular vacu¬ 
oles of the interior of the young oogonium (pi. 11, fig. 10) begin to 
disappear and in this region the cytoplasm becomes much more reg¬ 
ularly vacuolate. In the meantime, in the region of the oogonial 
wall, certain vacuoles at definite distances from each other begin to 
increase in size. This growth of the peripheral vacuoles continues 
at the expense of those in the interior until the cytoplasm of the 
latter is quite uniformly coarse meshed. In the meantime, or even 
before these changes, the nuclei have taken positions in the cyto¬ 
plasm separating these vacuoles. Figure 11 (plate 12) represents 
an oogonium at about this stage of development. It will be observed 
that the conspicuous vacuoles of figure 10 (plate 11) have practically 
disappeared from the interior and new ones have formed in the 
periphery. 
Figure 11 (plate 12) represents the beginning of another impor¬ 
tant cytoplasmic change to which attention should be called. In 
two or three places in the cytoplasm of the section here represented, 
there are distinct, fine meshed patches. In other sections of this 
