4H 
Lawson .— The Gametophytes and 
canals or archegonial chambers occur in all Coniferales, where the individual 
archegonia are isolated from one another, but as a rule they are quite 
shallow. In Sdadopitys, however, they are very deep—so deep that the 
mature archegonia eventually find themselves buried in the prothallial tissue 
a considerable distance behind the apex, as shown in Figs. 44 and 48. 
Stages in the development of the archegonial chamber may be seen in 
Figs. 42, 43, and 44. 
Meantime, the neck-cells have divided repeatedly, forming a single tier. 
At maturity these cells partly separate from one another on the outer side and 
spread out in a fanlike fashion. Directly under the neck-cells the central 
cell is quite narrow, but broadens out rather abruptly, as shown in Figs. 43 
and 44. There is thus formed a narrow pocket near the neck, and in this 
pocket the nucleus remains throughout the developmental stages of the 
central cell. 
When the latter reaches its full size, the nucleus undergoes a division 
which results in the organization of the egg nucleus and the ventral canal 
nucleus. The spindle is formed directly under the neck, as shown in 
Fig. 45. A later stage of this mitosis is shown in Fig. 46, where the chromo¬ 
somes are at the poles. A careful search was made for a ventral canal cell 
membrane, but although all stages of this mitosis were observed, no such 
membrane could be found. I am quite convinced that a cell-wall is not 
formed after this division. A considerable number of archegonia showed 
the condition represented in Fig. 47, where the ventral canal nucleus was 
found lying freely in the cytoplasm just above the egg nucleus. It will be 
remembered that among the Abietineae a definite membrane is formed 
which separates the ventral canal cell from the egg-cell. In a previous 
memoir (Lawson, ’07 and ’ 09 ) I have called attention to the probable 
phylogenetic importance of this. In the present case of Sdadopitys the 
absence of this membrane becomes interesting when we couple it with the 
fact that the functionless prothallial cells of the pollen are also absent. It 
would almost seem that there had been a simultaneous elimination of these 
vestigial structures. 
The egg nucleus and ventral canal nucleus are no sooner formed than 
they both undergo a change. The latter immediately disorganizes and 
functions no further, while the former enlarges enormously and moves down 
and takes up its position in the centre of the cell. Mature archegonia 
ready for fertilization are shown in Figs. 44, 48, and 49. 
Fertilization. 
As in the Abietineae and Cephalotaxus , the arrangement and grouping 
of the archegonia are such that it is possible for the contents of one pollen- 
tube to fertilize but a single archegonium. After passing through the 
nucellar tissue, the pollen-tube enters one of the long archegonial chambers, 
