of Fertilization in Angiosperms. 695 
Ginkgo (Hirase, 24 ), and Zamia (Webber, 41 , 42 , 43 ), and the 
generative nuclei were represented as much reduced sperma- 
tozoids, the existence of which formed a fresh phylogenetic 
link between the Cycadeae and Angiospermae. This hypo¬ 
thesis has been discredited by later work. The absence of 
cilia could be explained away so long as the vermiform 
nuclei had not been seen outside the embryo-sac, for Guignard 
pointed out ( 5 , p. 375) that the cilia of antherozoids disappear 
as soon as they enter the archegonium. But in Silphium 
(Merrel, 31 , p. 113, Fig. 61) the elongated male nuclei have 
been observed in the pollen-grain without any trace of cilia. 
Moreover, the small quantity of cytoplasm which enters the 
embryo-sac with each generative nucleus is in some cases at 
least quite undifferentiated (Guignard, 5 , p. 375, Figs. 14, 16, 
18), Guignard himself has shown that in Endymion nutans 
( 4 , p. 195, Figs. 21, 22, 23) the generative nuclei do not 
assume the vermiform shape. Thus in a plant so nearly 
allied to Lilium as this, the only character which suggested 
automatic motion is absent, and this fact in itself affords a 
strong reason for attaching no phylogenetic importance to 
the shape of the nuclei. 
Finally, Strasburger has once again followed the whole 
process of fertilization in the living ovule of Monotropa . His 
results, so far as they affect our point, are briefly these. The 
polar nuclei are connected with the egg-apparatus and with 
the antipodal cells by thick strands of cytoplasm which are 
in constant streaming movement. The contents of the pollen- 
tube when discharged reach down to the egg-apparatus. One 
generative nucleus can be identified as soon as it touches the 
nucleus of the egg-cell. The other cannot be distinguished 
with certainty until it has been in contact with the central 
nucleus of the embryo-sac for some time. But it is almost 
certainly carried down by the current in the strand which 
joins the egg-apparatus to the central nucleus, and a swelling 
in this strand probably indicates its passage. Fixed and 
stained preparations confirm these observations. Both genera¬ 
tive nuclei can be recognized in such preparations from the 
