286 Lazos on . — The Gametophytes and Embryo of the 
Fig. 3 represents a young pollen-tube more highly magnified, indicating the 
appearance and position of the body-cell and tube-nucleus. As shown in 
Fig- 4 > the older body-cell of Thuja orientalis differs slightly from that of 
Libocedrus in having a greater quantity of starch and food granules in its 
cytoplasm. Fig. 5 represents a mature male cell just previous to its entrance 
into an archegonium. 
From Land’s (■’ 02 ) account of Thuja , Coker’s (’ 04 ) account of Taxodium , 
and my own observations on Cryptomeria (' 04 ), Libocedrus , Thuja , Cupressus, 
and Chamaecyparis , there seems to be a striking uniformity throughout the 
Cupressineae in regard to the history of the male gametophyte. Such a close 
similarity in the microspores and pollen-tube structures apparently does not 
prevail between the members of any other group of the Coniferales. 
The Female Gametophyte. 
The first collections of material for the study of the megaspores in 
Libocedrus were taken early in March, but it was found that the megaspore 
mother-cells do not become differentiated until just about the time of pollina- 
tion. PI. XXIV, Fig. 8 represents a section of an ovule taken March 23. 
At this time the integument extends for a considerable distance beyond the 
apex of the nucellus, and the micropyle is open. The nucellus itself is quite 
large and flat on the top. The megaspore mother-cells make their appear- 
ance in the middle region of the nucellus in a position in line with the point 
of insertion of the base of the integument, as indicated in Fig. 8. Two 
mother-cells are generally developed ; occasionally but one was found. 
They very soon become differentiated from the surrounding tissue by their 
conspicuously large nuclei and their densely granular cytoplasm. Before 
dividing they become three or four times the size of the neighbouring cells. 
Fig. 9 represents two mother-cells lying side by side just before the first 
division. The spindle stages of this division were not found, so that I am 
unable to give an account of the chromatin at this critical time. Numerous 
preparations showed the megaspores after division, and from a study of 
these there is no doubt that each mother-cell dividing twice gives rise to 
four megaspores. Fig. 10 shows four of the cells after the first division, and 
Fig. 11 represents a section through eight spores soon after the second 
division. The spores are arranged in two rows- — four in each row — and 
have the appearance of those found in Cryptomeria rather than the arrange- 
ment figured by Coker (’ 04 ) for Taxodium. In Taxodium , however, 
there is but a single mother-cell organized, while in Cryptomeria there are 
three or four. At the stage shown in Fig. 11 all of the megaspores in 
Libocedrus look alike, and it is quite impossible at this time to say which 
one will develop into the prothallium. Surrounding the spores there is 
a single layer of loose cells, which may represent a tapetum. If such, it is 
a very poorly developed one, and by no means resembles that in Taxodium 
