226 Nichols, A morphological study of Juniperus communis var. depressa. 
nuclear thread appears as a slender, deeply staining band of uni¬ 
form thickness (fig. 82). The spindle is at first multipolar, but it 
soon becomes a multipolar diarch, the upper extremity of wbicb is 
yery broad, while the lower bundles of fibers converge toward the 
center of the asteroid, thus giying to'the whole figure somewhat 
the form of an inverted, truncated cone (fig. 88). With the Seg¬ 
mentation of the spirem and the Orientation of the chromosomes at 
the equator the nuclear membrane disappears, leaying the spindle 
surrounded by the cjToplasm of the central cell, and the multipolar 
diarch soon becomes bipolar. The axis of the spindle may be 
parallel to that of the archegoninm, but more frequently it is in- 
clined at an angle. Frequently the spindle is some distance below 
the neck cells. 
The daughter chromosomes, as they approach the poles, are 
U or V shaped (figs. 84, 85). At the poles the chromosomes 
rapidly draw together, becoming separated from the surrounding 
cytoplasm by membranes, and two resting nuclei are developed. 
No cell plate is formed, nor is there any indication whateyer that 
a wall is ever developed between the ventral canal nucleus and 
the egg nucleus. 
The two nuclei are at first yery similar in appearance, but 
the egg nucleus matures rapidly, while the ventral canal nucleus 
develops slowly and as a rule disintegrates before fertilization. 
Usually the ventral canal nucleus lies above the egg nucleus, but 
one case was found (fig. 91) in which these relations were reversed, 
a condition previously described by Coker (1903 b) in Tcixodium. 
Figs. 86 and 87 show two unusually well developed ventral canal 
nuclei. No evidence was found to support the theory (cf. Cham- 
berlainl899) that this nucleus is the homologue of the egg nucleus, 
but very often, as noted by Coker (1902, 1903b) in Podocarjnis 
and Tcixodium, by Land (1902) in Thuja, and by Noren (1907) 
in J. communis, the ventral canal nucleus persists for a long time. 
Figs. 88 and 89 show such nuclei in archegonia where the egg 
has been fertilized and the development of the proembryo has 
begun. Sometimes they undergo division (fig. 90) and this division 
is mitotic. 
Incidentally it may be noted that in this species archegonia. 
occasionally are found superposed one above the other (fig. 91) or 
more or less deeply imbedded in the prothallium. Similar cases 
are described in Picea and Abies (Miyake 1903a, 1903b), and in 
Pinus (Ferguson 1904), while analogous conditions occur in the 
Bryophytes (Coker 1903a). 
Surrounding the archegonium complex is a fairly well defined 
layer of jacket cells (fig. 95), while the walls of the egg cells are 
thin, except in the upper part, and no structures are visible which 
can be interpreted as pits. Stopes and Fujii (1906), however, 
have recently shown that even in those Gymnosperms where the 
thick wall of the egg is perforated by pits, the latter are closed 
by definite membranes which are pierced only by delicate threads 
of cytoplasm, so that the actual transfer of solid . substances 
