- 51 
material at hand, only saying that there are “two nuclei below 
the egg, and from the lines of cytoplasm one seems to be the 
synergid which has moved to that position‘. (Pacr, Fig. 42 on 
Plate XXV should demonstrate these lines of cytoplasm, but in 
other figures e.g. 43 and 51 nothing of the kind is to be seen). 
4°. It is well-known that the entering of the pollentube 
means the immediate destruction of the synergid. All figures of 
just fertilized embryosacs, published by Pacr, seem to furnish 
proof of this occuring also in Cypripedium. On Plate XXVI, 
Fig. 44 she figures a synergid in which the pollentube has just 
entered; the nucleus of this synergid is evidently desintegrating. 
Her Plate XXV, fig. 48, at a little later stage, shows the two 
fusing nuclei at the bottom, while in the synergid there are two 
male nuclei and a stained thing which must be the last remnant 
of the synergidnucleus. Her Plate XXVI, fig. 45 represents 
double fertilization, while in the upper half of the embryosac 
the deeply stained remains of both synergids are to be seen. 
Our own suggestion about the development runs as follows: 
In the two-nucleate stage there is a primary micropylar and a 
primary chalazal nucleus (Pacer, Plate XXIV, Fig. 24). Let us 
follow the history of the micropylar one first. The direction of 
the spindle in the division of this nucleus is | (Pacz, Plate 
XXIV, Fig. 25). But this is not the only division as Pace 
Supposed. It is followed by a division of the upper daughter 
nucleus only, giving rise to the two synergid nuclei. The other 
nucleus remains undivided and becomes the egg (Pace, Plate 
XXIV, Fig. 26). As to the chalazal group only one division 
of the primary chalazal nucleus occurs. As a rule the prim. 
chal. nucleus remains undivided until just before fertilization 
(Pacz, Plate XXIV, Fig. 26, Plate XXV, Fig. 29, 30), thus pre- 
senting a really four-nucleate embryosac. Then it divides, the 
two daughter-nuclei staying close together (Pacx, Plate XXV, 
Fig. 42, 43, ete.) and acting as embryosac-nucleus. At fertili- 
zation the pollentube enters one of the synergids (Pacz, Plate 
XXVI, fig. 44). The nucleus of this synergid at once begins to 
degenerate (Pacr, Plate XXVI, Fig. 44). A few moments later 
two male nuclei have entered the synergid, whose nucleus is 
