360 Miyake. — On the Development of the Sexual 
nucleus, from which the lower spindle arises, as described 
in Tsuga by Murrill (’ 00 ), has been observed in Picea. 
The ventral canal-cell shows signs of disintegration very 
soon after its formation. The nuclear membrane seems to 
break down very soon, and the nuclear substance becomes 
scattered throughout the cell. In the mature archegonium 
ready for fertilization, the ventral canal-cell usually appears 
as a lenticular or crescent-shaped cap over the top of the egg, 
with a deeply stained mass of granular substance ; and a dis- 
tinct nucleus is no longer visible in it (Figs. 34 , 35 , 48 ). 
In a few cases a fibrous structure, as observed by Black- 
man (’98) in Pinus sylvestris , was found in the ventral canal- 
cell of Picea. It may probably represent the remains of the 
spindle-fibres, as suggested by Blackman. 
In several preparations showing the division of the central 
cell, I was able to count the number of chromosomes, and 
twelve, or approximately twelve, were always found, as 
already noticed by Blackman (’98) and Miss Ferguson (’01 b) 
in Pinus , instead of eight as counted by Dixon (’94). The 
number of chromosomes in the dividing nuclei of the sheath- 
cells and other cells of the female prothallium has always 
been found to be approximately twelve, as already found 
to be the case in Pinus by Blackman (’98), Chamberlain (’99) 
and Miss Ferguson (’00 b), while their number in the cells 
of the nucellus was invariably more than twenty, the actual 
number being very likely twenty-four. 
Maturation of the Egg. 
The egg-nucleus, soon after it is formed, begins to increase 
in size, becoming considerably enlarged before the disappear- 
ance of the spindle- fibres (Figs. 47 , 48 ). As the nucleus 
moves down towards the centre of the egg, it continues to 
enlarge until the centre is reached (Figs. 34 , 35 ). After the 
division of the central cell, the few vacuoles, if there are any, 
in the cytoplasm gradually disappear, and at the same time 
an increase in the number of proteid-vacuoles takes place. 
Each proteid-vacuole at first contains a number of granules 
