162 BOTANICAL GAZETTE [SEPTEMBER 
center is the opaque globule immediately surrounded by « 
lightly stained zone. After reaching the condition of maximum 
development the structure rapidly loses character, disap 
pearing entirely just before the antheridial tube discharges its 
contents. 
A summary of the history of the central structure may be 
given as follows: it first appears in zonation, and reaches is 
maximum development when the daughter nuclei of the fis! 
mitosis pass into the oosphere; after that it rapidly degeneratts 
although traces of its presence sometimes persist nearly to the 
time of fertilization. A body of apparently similar nature ¥® ] 
mentioned by Wager as occurring in the oosphere of A. candids 
and my own as yet incomplete observations on that species indi | 
cate that the body seen in A. candidus and the central globule o | 
A. Bliti are homologous structures, although they differ much 0 
certain details. I find also a structure very like the one above 
described in the oosphere of A. 7; ragopogonts and A. Portulat 
and believe that we have here an organ of the oosphere, perhaps 4 
regularly present in the whole genus Albugo, if not ™ the | 
oospheres of other related genera. It appears with such co 
stancy at certain important stages in the life history of the spe 
cies, and passes through such a definite course of developmet : 
that its presence seems to be of importance. May it not “ 
It should be called to mind in this connection that Dango : 
noted in each of the numerous oospheres, in certain eet : 
the Saprolegniaceez and Peronsporee, a cent 
appeared just before fertilization. Various interpre 
been given to such structures by different writers, early fs 
ers mistaking it for a nucleus. Dangeard supposed - “ 
but Wager thought that Dangeard was probably mistaken 
that the structure is truly a central body such a8 95 
found in A. candidus. The descriptions and time of at 
make it seem quite possible that the body noted in the o 
g of the Society 
*MR. SWINGLE expressed such views at the meetin 
Morphology and Physiology at Ithaca, December 1897- 
