Cupressineae , with special reference to Libocedrus decurrens . 295 
they divide simultaneously. It will also be seen from this figure that the 
two spindles of this division lie one behind the other, with their long axes 
parallel with the long axis of the archegonium. The four daughter-nuclei 
resulting from this division are thus arranged in a single row, and not in the 
tetrad fashion as seems to be the case at this stage in Taxodium (Coker, ’03). 
Land (’ 02 ) also figures a somewhat different position of the spindles of the 
second division in Thuja occidentalis. As only two or three preparations 
showed this stage of the embryo, I cannot say how constant or variable 
the position of the first four nuclei may be, but judging from the stage just 
before the third division, and also from a study of these stages in Crypto - 
meria , I am inclined to believe that there may be a considerable variation in 
the position of the free nuclei up to the time they arrange themselves in 
tiers and definite walls are formed between them. 
Some time before and during the second division the archegonium 
becomes differentiated into two distinct regions, and this seems to be 
brought about by the sinking of all the starch, ‘ proteid-vacuoles,’ and other 
food substances into the basal region of the fertilized egg in very much the 
same manner as that which I have reported for Cephalotaxus (Lawson, ’07). 
It is only this nutritive or basal region of the archegonium which now 
concerns the development of the embryo, and this is indicated in Figs. 31 , 
33. 34, and 35 . 
No sooner are the first four nuclei organized than they prepare for the 
third mitosis. This latter division is also simultaneous, and it results in the 
formation of eight free nuclei in the pro-embryo. From Land’s (’02) 
account of the embryo of Thuja ; Coker’s (’03) account of Taxodium , and 
my own observations on Cryptcmeria, Thuja , Libocedrus , and Cupressus , it 
seems that the organization of eight free nuclei in the pro-embryo, before 
the formation of cell-walls, is a constant feature of the Cupressineae. 
Fig. 34 shows a stage just previous to the formation of the first cell- 
walls of the embryo. These walls are obviously formed in the same manner 
as they are in Cryptomeria (Lawson, ’04). The spindles of the first two 
divisions disappear entirely after the organization of the daughter-nuclei, but 
the continuous fibrils of the spindles of the third division persist until 
membranes are formed from them midway between the nuclei. The cells 
of the pro-embryo, as a result of these divisions, are arranged in three 
distinct tiers — or rather two tiers of cells and one tier of free nuclei, for 
the upper tier or rosette are not surrounded by walls. The middle tier of 
cells very soon begin to elongate, and are thus easily identified as suspensors. 
The end tier of cells or embryo cells proper show very little enlargement, 
and no more merismatic activity whatever until they have been carried for 
a considerable distance into the endosperm tissue by the enormous elonga- 
tion of the suspensors. In this regard Libocedrus and other Cupressineae 
are very unlike that of Cephalotaxus , for in this latter genus the embryo cells 
