nee errr a ee ee ee age 
1912] CHAMBERLAIN—CERATOZAMIA II 
canal nucleus and egg nucleus, while the archegonial chamber is 
still quite shallow and the pollen chamber only half way through 
the nucellus, their tips have already reached the megaspore mem- 
brane. They contain starch and occasionally the tube nucleus 
wanders into one of them, but the tube nucleus, at the stage shown 
in figs. rr and 12, is almost invariably found in the enlarged por- 
tion of the tube and is usually near the body cell. Only in very 
early stages is it found in the primary haustorium. 
As the tissue of the nucellus breaks down beneath the advancing 
pollen tubes, the secondary haustoria, especially those extending 
directly downward, become bent and twisted and finally appear as 
an irregular tangle pressing against the megaspore membrane 
(fig. 12). The tissues of the nucellus disorganize so rapidly that 
the secondary haustoria do not hold back the basal end of the tube, 
but advance with it. The disorganization which forms the pollen 
chamber is very extensive, including not only the region occupied 
by the basal ends of the tubes, but finally all the tissues in the region 
of the secondary haustoria. 
The division of the generative cell into the stalk and body cells, 
a division which I was not able to secure in cultures, takes place 
quite promptly after the pollen grains have reached the pollen 
chamber, probably within a week after pollination. From a record 
of various cones of various seasons, the time at which the body 
cell divides shows considerable variation, the division being noted 
as early as the middle of June, and as late as the first of August. 
The most usual time is the first week in July. 
In nearly all cases, two sperms are produced from each body 
cell, but four sperms were found in a few cases. In two cases, four 
sperms were found in isolated pollen tubes mounted without 
sectioning; in one case, four were found in one tube in serial sec- 
tions; and in another case, shown in fig. 13, the body cell had 
divided, forming two cells, each with the aspect of a body cell and 
with two blepharoplasts, so that there is no doubt as to the manner 
in which the four sperms are formed. 
At the division of the body cell, the mitotic figure is small and 
entirely intranuclear during the metaphase, but after the nuclear 
