VOLS Recent Literature. 107 
the spore, but that of these three usually but one persists, the 
_ first two formed being disorganized soon after they are cut off, so 
that in the ripe spore but one of these is to be readily seen. This 
small cell he considers homologous with the antheridium of the 
heterosporus Pteridophytes. This antheridial cell often divides 
into two, a small stalk-cell, and a larger one which represents 
the real generative part. He found that wherever this anther- 
idial body was pluricellular, that it was always formed before the 
dehiscence of the sporangium. 
As the pollen-tube grows, the generative cell of the anther- 
idium becomes detached and passes down the pollen-tube, where 
it divides into two cells which must be regarded as homologous 
with the sperm-cells of the lower archegoniates. In the Cupres- 
sineze both cells are functional, and thus two archegonia may be 
fertilized by a single pollen-tube; in the Abietineze, however, 
only one of the two sperm-cells appears to be functional. In the 
meantime the nucleus of the pollen-tube has also divided, but 
these nuclei take no apparent part in the process of fertilization, 
contrary to the earlier views of Strasburger and others. Fertili- 
zation is effected by the discharge of the contents of the genera- 
tive cell through the end of the pollen-tube into the archegonium. 
From a study of the three genera of the Gnetaceze—Gnetum, 
Ephedra, and Welwitschia, our author concludes that they repre- 
sent the end members of three separate lines of development 
within the Gnetaceze, which together with the other Gymnos- 
perms have had a common origin lower down in the system. 
After a careful study of the alleged differences in the male and 
female nuclei with reference to different stains, he comes to the 
conclusion that this difference depends entirely upon the amount 
of cytoplasm taken up by the nucleus for its nourishment. In 
all cases he claims that the nuclein itself is ‘‘ kyanophil’’—that 
is, has a special avidity for blue stains, when compared with the 
cytoplasm; in all cases during nuclear-division the nuclear-seg- 
ments are distinctly kyanophil- He therefore concludes that 
when the female nucleus is erythrophil it is due to the presence 
in it of unassimilated cytoplasm. 
The second part of the work deals with the formation and 
structure of zoospores and spermatozoids, and the process of fertil- 
