Eames. — The Morphology of Agathis australis . 5 
The formation and germination of the megaspore were not seen, nor 
was material available to determine the method of wall formation within 
the embryo-sac. The definite arrangement of the cells, especially at the 
micropylar end, points clearly to a centripetal growth not different from that 
of other Conifers. The mature gametophyte is distinctly club-shaped, the 
upper larger portion bearing the archegonia (Fig. 2). The cells of this latter 
portion are elongated radially and arranged rather symmetrically, strongly 
suggesting the huge elongated cells, the ‘ alveoli of endosperm formation. 
In the basal portion there is much less regularity, and the cells are smaller. 
At this stage, just before the maturity of the egg, the cells of the game- 
tophyte are not rich in cytoplasm, though they are multinucleate, especially 
those of the central portion. 
The archegonia are numerous and arranged irregularly, many of them 
being deep-seated. They occur only upon the upper third or half of the 
gametophyte. The number is variable, from three to twenty-five in the 
ovules studied, eight to fifteen being the commonest numbers. Though in 
general the method of placing is indefinite, there is often a noticeable 
tendency to assemble them in three groups : a small terminal cluster, and 
two uneven encircling crowns at short intervals below. Within these 
groups no' order is distinguishable ; in fact, all transitions are found from the 
solitary archegonium to a sort of archegonial complex. Some difference in 
age is discernible, indicating an acropetal development. When fertilization 
is occurring in lower archegonia the ventral canal nucleus may not as yet 
have been cut off in the apical archegonia. The megaspore-membrane cap 
protects these young archegonia, which are not ready for fertilization at the 
time the first male cells come down, shunting the latter off and down to the 
thinner lower regions of the megaspore membrane, under which are situated 
the greater number of archegonia and the more mature eggs. Fig. 10 shows 
the course taken by pollen-tubes, how they have passed by one of the nearest 
upper archegonia and fertilized those below. The two lower archegonia 
contain proembryos distinguishable in the figure by their dark hue. 
The archegonia vary much in position in the gametophyte ; some are 
very deep-seated, others superficial. The majority are embedded beneath 
several to many cells. That some of the archegonia are derived from 
peripheral cells seems apparent, and it is doubtful if any are actually deep- 
seated in origin. In those of shallow position the neck-cells, as seen in 
vertical section, lie in the unbroken line of the outermost layer of cells ; 
in the more deeply situated a narrow canal reaches to the surface from the 
neck, and evidence of overgrowth ..by the surrounding cells is suggested. 
Where the canal is completely closed, its former position may often be 
discerned, so that its existence at one time is probable in all cases. The 
complete burial of the archegonium is compensated for by the unusually 
strong erosive capacity of the pollen-tube. Fig. 11 presents a fairly 
