18 BOTANICAL GAZETTE [JANUARY 
separate layer of the seed coat, especially on the right side of the 
figure. Its tissues become lignified in precisely the same manner 
as those of the integument and scale. Fig. 47 shows a section 
through the developing testa at about the time it begins to become 
woody enough to be unsuitable for cutting in paraffin. The outer 
layer consists of a conspicuous epidermis filled with mucilaginous 
contents. Beneath this there is an irregular layer of cells with 
darkly staining contents, probably largely tannins. On the inner 
border next the nucellus there is a less conspicuous epidermis 
underlaid by several layers of elongated, thin-walled cells with 
very scanty contents. The larger part of the testa consists of the 
irregular cells shown in the central part of the figure. These cells 
become elongated and more tangled as the seed grows larger. At 
first their walls are very woody and tough, but not at all brittle. 
In the adult seed they turn brown, become much more brittle, and 
when dry are capable of being in part reduced to fine brown powder 
by crushing. The changes in the integument and nucellus are of 
the same kind as those occurring in the scale itself. The result is 
that in the mature seed all these parts have developed into a homo- 
geneous structure, and ovule and scale have united to produce the 
seed. It resembles what might be expected to develop from a 
naked anatropous ovule. 
Discussion 
Araucaria and Agathis resemble one another very closely, 
differing only in minor points. They present a number of sharp 
contrasts to most other conifers. Pollination of the ovuliferous 
scale, very long and extensively branching pollen tubes, extruding 
nucelli, precocious division of the body cell, large actively motile 
male cells, and concentric proembryos will serve to recall some of 
these points of difference. Excepting Saxegothaea, with its pro-. 
truding nucellus near which the pollen germinates, these features 
are very different indeed from the corresponding ones in the other 
families of Coniferales. 
These resemblances to Saxegothaea have attracted the attention 
of a number of botanists (16, 22, 24, 25a, 26). Taken in connection 
with other resemblances they are sufficient to create a strong 
