Igor] GAMETOGENESIS AND FERTILIZATION IN ALBUGO 259 
Fig. 9. Transverse section of the antheridial tube, showing its multi- 
nucleate character. Oosphere of about the age shown in fig. 7. X 13 
Fig. 10. Nuclei pairing after opening of antheridial tube, a distinct aa 
surrounding oospore; remains of antheridial tube visible in periplasm; 
degenerating nuclei in antheridium. x 8 
Fig. 11. Fusion complete; stage before accumulation of oils and before 
the outer walls are complete. x 857. 
Fig. 12. Portion of mature wall. x 857. 
PLATE Il, Albugo Candida. 
Fig. 13. Very young coenocentrum showing that the granules pass in 
from the surrounding ooplasm; oosphere slightly younger than stage next 
a xX 1366. 
G. 14. Early oogenesis; oosphere roughly outlined by a withdrawal of 
the icin from the oogonium wall, leaving only a loose periplasm 
ehind; nuclei approximately in metaphase; coenocentrum well developed. 
1366. 
Fig. 15. After first division; several ora clustered around the coeno- 
centrum ; some already gone to the periplasm. 
Fig. 16. Later than fig. 75; nearly all of we nuclei have retreated to 
the periplasm; those remaining in the ooplasm in mitosis. X 1366. 
Fig. 17. Later than fg. 76, mitosis complete. x 1366. 
Fic. 18. Very slightly later than fg. 77; nucleus in metaphase, aude 
Owing to attraction by coenocentrum; coenocentrum densely and coarsely 
granular, 
FIG. 19. Two nuclei attached to coenocentrum; one in late anaphase, 
the aie | in telophase ; coenocentrum more dense than in fig. 78 ; oosphere 
Similar to that shown in fig. 7g. X 13 
Fic. 20. Similar to fiz: 79; one eee in late anaphase attached to 
coenocentrum. x 1366. 
Figs. 21, 22. One nucleus much enlarged attached to coenocentrum by a 
pseudopodium-like extension ; all other nuclei lie in the periplasm. X 1366. 
IG. 23. Before fusion; male and female nuclei and a supernumerary 
nucleus near the coenocentrum. X 1366 
Fig, 24. Metaphase of first division of fusion nucleus. X 1366. 
Fic. 25. Anaphase of first division of fusion nucleus. X 1366. 
Fig. 26. An antheridial tube bearing two nuclei; the female nucleus 
lying in aha ooplasm near the coenocentrum. X 1366. 
PLATE Ill, Albugo Tragopogonis. 
Fig. 27. Early stage of oogenesis; protoplasm collected in one central 
mass; nuclei approaching metaphase; a slight indication of the coenocen- 
trum apparent in the center. x 
