436 Ferguson . — The Development of the Egg and 
not appeared. In general, Blackman’s observations have been 
confirmed for Pinns Strobus, and other interesting phenomena, 
not yet recorded as occurring in plants, have been noted. 
Early Development of the Archegonium. 
The archegonia in Pinus , as is well known, do not make 
their appearance until the ovules have entered upon the 
second year of their development. In material fixed during 
the latter part of May, the cells comprising the upper part of 
the prothallium, that is, its micropylar end, are seen to be 
much more regular in shape and arrangement than those 
which constitute the rest of the endosperm. Cell-division is 
now taking place in any or all parts of the prothallium, but 
the regular, more or less rectangular cells in its upper portion 
are especially active, and they are comparatively rich in 
protoplasm. Very soon some of the uppermost of these cells 
cease to divide, but continue to grow, so that they are dis- 
tinguished from the adjacent cells by their greater size, larger 
nuclei, and more vacuolate cytoplasm. These are the initial 
cells of the archegonia (PI. XXIII, Figs, i and 2). At this time 
the prothailium has, as a rule, become a solid mass of tissue, 
although it not infrequently happens that there still remains, 
at its centre, an open space into which the cells of the grow- 
ing endosperm have not, as yet, extended. 
While the primary cell of the archegonium is still quite 
inconspicuous it divides, giving rise to a small, upper cell, 
the mother-cell of the neck, and a large, lower cell which 
forms the venter of the archegonium (Figs. 3 and 4). The 
small cell immediately divides by an anticlinal wall, and the 
two cells, thus formed, divide by walls that are perpendicular 
to the first, the resulting four cells all lying in the same plane. 
These constitute what may be called the normal neck in Pinus 
Strobus (Figs. 5-9 and 12). Frequently, however, two of 
these cells divide again, as figured by Strasburger (’ 69 ), the 
six cells being arranged in a single layer (Figs. 10, 35, and 39). 
Occasionally all four cells divide by anticlinal walls, the neck 
then consisting of eight cells, all of which lie in the same 
