7 
E antes. — The Morphology of Agathis australis. 
tance to the entrance of the pollen-tube is well shown in Fig. 38. This 
is a transverse section of a neck and the surrounding tissue. The tip of 
the pollen-tube has eroded the gametophytic cells around the neck com- 
pletely, leaving the latter entirely unaffected. On this account the neck 
complex is frequently freed as a whole when the male cells break through, 
and is thrust aside, in some instances being even carried with the male 
cytoplasm into the centre of the archegonium. 
The central cell in the youngest stage studied presents the condition 
shown in Fig. 12 : cytoplasm thin and strongly vacuolate — as usual in the 
coniferous archegonium at this time ; a small nucleus with little chromatin, 
and a brilliant nucleolus. The position of the nucleus is upper central, 
though it is not rarely found towards the base of the cell. An upward 
migration must occur before the cutting-off of the ventral canal nucleus. 
The formation of the latter occurs in the uppermost portion of the cell, 
and nearly always well to one side, instead of below the neck-cells. Figs. 13 
and 1 4 show the ventral canal nucleus and the young egg nucleus soon 
after formation. Fig. 13 is a somewhat tangential section of the arche- 
gonium and does not show the neck-cells. But there is no question as 
to the identity of the nuclei presented, as the series reveals the archegonium 
unruptured, and further, the male nucleus is very different in size and 
appearance. In two or three cases the mitosis was found to occur centrally, 
and Fig. 14 shows a rare case of median position of the ventral canal 
nucleus. In all the many cases where the latter was cut off to one side, 
that which may be called the abaxial side of the archegonium was chosen — 
referring of course to the oblique, lateral archegonia. One can see no 
significance in this fact, however. 
Immediately after division the two nuclei are about equal in size — 
perhaps exactly so — and cannot at first be told apart except in position. 
The egg nucleus grows rapidly, retreating towards the centre of the cell ; the 
ventral canal nucleus immediately begins to disorganize, disappearing com- 
pletely in a short time. No evidence of wall formation, or of differentiation 
in the surrounding cytoplasm suggestive of cell limitation, was seen. So 
rapid is the disintegration of the canal nucleus that normally it is not to be 
found when the egg nucleus is half-grown, and no trace exists when matura- 
tion is complete. In Figs. 13 and 14 the nucleus is already beginning 
to disorganize. 
Immediately after the central cell nucleus has divided the vacuoles 
largely disappear from the central portions of the cytoplasm (Figs. 1 3 and 14). 
PI, II, Fig. 19 shows the young egg nucleus and the condition of the cyto- 
plasm at this time, under considerable magnification. The nucleus develops 
rapidly. The mature egg nucleus is represented in Fig. 20 ; the nature of 
the surrounding cytoplasm is also indicated. (The sections of archegonia 
shown in Figs. 19 and 20 are nearly transverse.) Large vacuoles are found 
