1899] THE COMPOUND OOSPHERE OF ALBUGO BLITI 237 
SUMMARY. 
1. The oogonium when cut off from the parent hypha con- 
lains about 300 nuclei, which enlarge and divide mitotically 
while the oosphere is being differentiated. 
2, The oosphere is differentiated through a massing of the 
cytoplasm of the oogonium. By this process the nuclei, usually in 
stages of mitosis, together with the vacuoles, are expelled from 
the central region, and there results a dense and coarsely vacuo- 
te periplaam. This condition occurs when the antheridial 
tube is very short. 
3. There is a stage called zonation in which the nuclei, usually 
metaphase, are lined up around the ooplasm, some of the 
spindles lying across the definite boundary that separates ooplasm 
tom periplasm. In the telophase of this mitosis about fifty 
daughter nuclei are found in the ooplasm. 
4 The antheridium contains at first about thirty-five nuclei 
omy divide twice mitotically, and simultaneously with the 
“sion in the oogonium and oosphere. 
oo. i” the entrance of the antheridial tube a papilla 
Projecting from the oogonium into the antheridium. 
6. The antheridial tube penetrates slowly, reaching the 
| *oplasm at the time of zonation, later entering the oosphere and 
—Ppearing as a conspicuously multinucleate structure. When it 
ao there are discharged about one hundred male nuclei which 
With the female nuclei in pairs. 
: a oc nuclei differ in form; the sperm being elon- 
a 3 € egg spherical. 
ae central body, the ccenocentrum, bpabbee a as 
: ‘ 5 Matures and disappears before fertilization. Its 
iy unknown. There is some evidence of its being a 
— SYNamic Femter of the comp d h 
9. The ioc: 7 re oosp ae oe 
oth a. ‘ are alike in the oogonium and antheridiu é 
ba os intra-nuclear and there are no extra-nuclear 
Md are —.. centrosomes are very prominent at metaphase, 
Ss uclear. They could not be distinguished in the 
