Sexual Organs of Phytophthora erythroseptica , Pethyb . 123 
resembles in all respects the club-shaped body seen in longitudinal 
section which we have called the oogonial incept. 
3. The wall of the antheridium is in favourable sections seen to be 
invaginated at the point where the oogonial incept seems to 
enter (Figs, 2, 13, 21). This can be most reasonably explained 
by assuming that the wall has been actually pushed in by the 
oogonial incept. 
4. A sheath of antheridial origin—staining orange and continuous 
with the invaginated antheridial wall—encases the lower part 
of the oogonial incept and extends up it for a greater or less 
distance (Figs. 13 and 21). This is difficult to explain except on 
the supposition that the developing oogonial hypha is within the 
male organ. 
5. The appearance seen in Fig. 5 would not be so common, the limits 
of growth of both organs being exactly the same, if one lay on the 
other. It is reasonable that such an appearance should be frequently 
presented if the oogonial incept be engaged in breaking through 
the wall of the antheridium. 
6. In stages like those shown in Figs. 6 and 7, c , the wall of the 
antheridium is distinctly discontinuous at the points where the 
oogonial incept is beginning to protrude. 
7. In the early stages of the emergence of the oogonium the frayed 
margin of the ruptured antheridial wall may be seen (Fig. 8). 
8. In Fig. 8 the distal margin of the antheridium is seen to be a 
straight line when looked down upon from above. This is most 
easily explained by conceding that it has been ruptured here by 
the emerging oogonium. 
9. As the oogonium assumes a spherical form it tends to distend 
the rim of the antheridium which is in contact with it and turns its 
margin outwards so that the top of the antheridium resembles the 
lip of a beaker. Beginnings of this condition are seen in Figs. 9, io, 
and 12. This could not take place if the oogonium lay outside the 
antheridium. 
10. In oblique sections the stalk of the oogonium may often be traced 
passing through the antheridium, entering below at one side and 
emerging above at the other, or vice versa. 
11. If the stalk of the oogonium be not within the antheridium it is 
not unreasonable to expect to see some indication of that condition 
occasionally among the very many thousand organs examined. No 
condition other than that of which Figs. 1, 14, and 16 are the general 
examples has ever been seen. 
If we may assume then that the oogonial incept is within the antheri¬ 
dium the question arises, How does it get there? The oogonial incept 
