6 oo Mur rill.—The Development of the Archegonium 
sperm-nucleus slips from the cell and conjugates with the 
egg-nucleus, the smaller one being gradually absorbed with 
the other structures derived from the pollen-tube. 
The functional sperm-nucleus flattens itself against the 
egg-nucleus in the form of a bi-convex lens, and the two 
nuclei soon come to lie in the space formerly occupied by the 
egg-nucleus alone, their membranes, however, remaining intact 
for a long time. In this condition the sperm-nucleus rapidly 
loses its density and constructs a delicate peripheral chromatic 
reticulum and larger central nucleoli, thus becoming a perfect 
resting nucleus similar to that of the egg. The chromatin of 
each nucleus collects in the form of a thick knotted thread 
near the centre of the separating partition, and the two masses 
remain distinct until the spirem-bands begin to segment. 
Just before the spirems are formed the separating mem¬ 
branes disappear and the nuclear cavities become united. 
The spindle then arises in a multipolar fashion between and 
among the two masses, twelve chromosomes being supplied 
from the chromatin of the sperm and twelve from that of the 
egg, as described by Blackman for Pinus Sylvestris. The 
mature spindle is broad with blunt ends, and the manner of 
division is typical. 
A second division succeeds the first without much delay, 
and the four resulting free nuclei soon attain full size and 
move to the base of the archegonium, where the young embryo 
becomes established in the manner already so well known 
among Conifers. 
The investigations leading to the results recorded above were 
conducted in the Botanical Laboratory of Cornell University 
under the direction of Professor George F. Atkinson, at whose 
suggestion this work was undertaken, and for whose kindly 
sympathy and invaluable aid in its prosecution I am deeply 
grateful. 
