14 BOTANICAL GAZETTE [JANUARY 
while his results were negative, I am inclined to believe they are 
entirely correct, for the entrance of the sperm into the egg in both 
Ceratozamia and Dioon seems to be independent of any chemotactic 
phenomena. 
The female gametophyte 
If strobili were numerous, Ceratozamia would be favorable for 
a study of the origin and development of the megaspore, for the 
strobili break through the bud scales at a very early stage. The 
earliest stage in any material shows free nuclear division in the 
megaspore. The general course of development is about the same 
as in Dioon edule (g), the principal differences being that structures 
are smaller, the mature gametophyte being about 2.5 cm. in length, 
and the archegonia at the time of fertilization seldom reaching a 
length of more than 3 mm. 
WARMING (10) in 1877 reported a ventral canal cell in Cerato- 
zamia robusta, but soon concluded that he had been mistaken. It 
is not surprising that he was in doubt, for the ventral canal nucleus 
in Ceratozamia mexicana is very small and usually disorganizes 
very promptly. The relative sizes of the ventral canal nucleus 
and the egg nucleus are shown in fig. 17, while 17a is a detailed 
drawing of the ventral canal nucleus shown in fig. 17. It is of 
special interest to note that the ventral canal nucleus does not 
always disorganize, but may enlarge, as it sometimes does in 
Pinus (11) and Ginkgo (12), and in such cases it is very probable 
that the egg may be fertilized by the ventral canal nucleus. I 
have seen two cases in Ceratozamia in which a large nucleus, looking 
like the nucleus of the sperm, was only a short distance from the 
egg nucleus, but no ciliated band could be found in the egg and the 
neck cells were still turgid. The objection is easily made that the 
failure to find the ciliated band is only negative evidence, but the 
band is so large and so persistent, that to one familiar with cycads 
the failure to find it at this early stage is conclusive proof that no 
band is present. Of course it might be suggested that only the 
nucleus had entered the egg, the band remaining outside, but in 
many cases the sperm, with the ciliated band, was observed inside 
the egg, sometimes being plainly visible in late free nuclear stages 
of the proembryo (fig. 20). 
