19 
E antes . — The Morphology of A gat his australis . 
4 protosiphonogamic ’ type of fertilization, the penetration by the pollen-tube 
of tissues about the ovule and of the integument, with the passage of a space 
in the attainment of the nucellus, is suggestive of angiospermous conditions 
and not of primitiveness. 
In the Gymnosperms generally the pollen-tube erodes a passage only 
to one archegonium — except in the case of the complex. In A gat his the 
tube goes from archegonium to archegonium. Is this a more simple con- 
dition than the common one ? 
The neck cells have lost their normal function, that of providing 
entrance to the egg-cell. They have become instead a serious obstacle to 
the advance of the male cells. Partial recompense is secured by eliminating 
the jacket cells contiguous to the neck, leaving normal, somewhat less 
resistant gametophytic cells. This is not a step in the reduction of the 
archegonium as a whole, that evolutionary tendency which results in the 
free egg of the higher Gnetales. Aside from the break at the top the 
jacket shows no signs of reduction. It is merely a little more complex 
than that of the Cycadales, Ginkgo , and the Abietineae. 
In the history of the female gametophyte probably the most prominent 
evolutionary tendency apparent in the series from the Pteridophytes to the 
Angiosperms is the reduction of the complex archegonium of the lower 
forms. The final result is the complete freedom of the egg nucleus. In 
the lower Gymnosperms the neck canal cells no longer appear. The ventral 
canal cell is next in line for elimination. This is completely accomplished 
within the Conifers themselves. The Abietineae form a definite cell ; in 
Taxns and Torreya even the nucleus has disappeared. In the Araucarineae 
the condition is that of most Conifers — a ventral canal nucleus is cut off, 
but no wall is formed. The nucleus itself disintegrates very rapidly. Cer- 
tainly in this respect the Araucarineae are less primitive than the Abietineae, 
and on an equal footing with some of the higher Conifers. 
The method of fertilization does not suggest resemblances to the lower 
Gymnosperms any more than to the Conifers as a whole, unless the very 
large male cell be compared with the sperms of the Cycads. But the ovule 
of Agathis gives no evidence of that ancient feature the pollen-chamber, 
nor do the male nuclei show signs of motility. A male nucleus of equal 
size with that of the egg occurs in Sequoia , another feature to add to the 
several in which parallelism has been emphasized. 
In the Cycadales and the Ginkgoales the extensive proembryo stands 
out as a presumably primitive feature. Since the proembryo of the Arau- 
carineae also sometimes fills the egg, Thomson (14) has noted a close 
resemblance. In all three groups free nuclear division proceeds to a stage 
well beyond that known in other Gymnosperms, at least eight consecutive 
divisions taking place in the first two and five or six in the third. But these 
are of an absolutely different character. In the Cycads and Ginkgo the 
