ALBUGO (CYSTOPUS). 97 
structure seem not unlike those of higher plants. The number of 
nuclei in the young oogonium, at this stage, varies with its size, the 
average being from 70 to 110. The antheridium, containing from 6 
Fre. 35.—Development of sexual organs and fecundation in Albugo (Cystopus) candida.—-(After Wager.) 
A, antheridium attached to wall of odgonium, just beginning to push out its conjugating tube; dense 
mass of cytoplasm and several nuclei seen near projection, 
B, young oégonium after its delimination from mycelium, with antheridium attached ; receptive papilla 
projects from odgonium toward antheridium ; nuclei seem to be entering prophase of division. 
C, later stage; protoplasm has contracted into a large central mass; nearly all the nuclei have divided, 
and are collecting at periphery of central mass ; the deeply stained mass of cytoplasm, a (central body, 
coenocentrum), is seen in center in contact with egg-nucleus; egg-nucleus is derived from one of the 
original nuclei of oédgonium. 
D, oégonium into which conjugating tube has penetrated ; differentiation of periplasm and oéplasm 
becoming apparent, though a plasma membrane has not been formed around the egg; in center of 
odplasm is the egg-nucleus near the dense mass of cytoplasm; in end of conjugating-tube is dense 
cytoplasm in which lies the male nucleus. 
E, later stage than D; apical wall of conjugating tube, becoming very thin; plasma membrane of ogg 
not yet formed. 
to 12 nuclei, now applies itself to the odgonium, The structure 
both of its nuclei and cytoplasm is similar to that of the odgonium. 
Soon after the two organs come into contact with each other, a portion 
