Embryo of Sciadopitys verticillata. 407 
Cupressineae, but in two free nuclei. From the large number of cases 
examined showing these stages, it became quite evident that there was no 
cell membrane separating these two male nuclei from one another. The 
two structures were found lying quite freely in the cytoplasm of the body¬ 
cell, as shown in Fig. 12, and one of them is slightly but distinctly larger 
than the other. Both of them are carried through the neck-cells and into 
the archegonium by the tip of the tube. In two cases they were found 
lying in the egg cytoplasm just below the neck-cells. One of these is 
represented in Fig. 49. 
The Female Gametophyte. 
The number of ovules produced on each ovuliferous scale is quite 
large. They varied from five to fifteen or more according to the position 
of the scale on the cone, the lower scales producing the larger number, 
and decreasing as the scales became smaller towards the apex of the cone. 
They first appear as minute papillae-like structures growing out at right 
angles to the dorsal surface near the base of the scale, and arranged in two 
or three rows more or less crowded together. The nucellus or sporangium 
proper is the first to develop, but this is very soon followed by the 
integument, which, in the earlier stages, appears as a ring of tissue 
surrounding the base of each papilla-like nucellus. This condition was 
found early in March, and from this time on a complete series of stages was 
obtained by collecting material every two or three days. The ovules take 
about four weeks in their development before they are in a condition to 
receive the pollen. During this period the integument grows a little more 
rapidly than the sporangium, so that at the time of pollination it projects 
a little beyond the level of the apex of the latter. 
The sporogenous tissue does not become differentiated until after the 
pollen has been received in the micropyle. Fig. 6 represents a longitudinal 
section of an ovule about three weeks after pollination. Although, as here 
shown, the pollen-cushion has been differentiated and the pollen received, 
and the micropyle nearly closed, there is as yet no trace of sporogenous 
tissue in the megasporangium. Except for the highly differentiated 
character of the pollen-cushion all of the cells of the nucellus resemble one 
another. During the last week in May, however, certain cells, deep in the 
centre of the nucellus at a point level with the insertion of the integument, 
become enlarged and take on a sporogenous character. These cells are 
few in number, and in one or two cases appeared singly. Whether they 
could always be traced back to a single cell I am unable to state, but it 
seems probable. These cells are not only large and with deeply staining 
nuclei, they are also actively merismatic. They divide rapidly and frequently, 
and soon give rise to a large and sharply differentiated sporogenous group 
