Notes. 
345 
spermatozoids of the lower and higher Cryptogams known till now, 
for it measures 82 \x. in length and 49 n in breadth. That of Cycas is 
larger than that of Ginkgo both in breadth and length. It is oval in 
shape. The head consists of three spiral windings in Ginkgo , and of 
four in Cycas, on which cilia, the organs of motion, are abundantly 
present. The tail is also formed, but is visible only after the element 
has broken out of the pollen-tube. Anatomically considered, it 
consists of a nucleus and cytoplasm, which covers it completely. 
If we examine the ovules both of Ginkgo and Cycas towards the 
time of fertilization, we find a quantity of sap present between the 
apical concavity of the endosperm-body and the nucellar skin. This 
sap is necessary for the act of fertilization, for spermatozoids, by 
swimming there, are able to reach the archegonia. For it is a remark- 
able fact that in our plants the pollen-tube is far apart from the neck- 
cells of the female organ. As is well known, in other Gymnosperms 
the pollen-tube penetrates in fertilization more or less deeply into the 
archegonia, but in our plants the tube does not come at all into 
contact with the neck-cells. We think that this fact explains the 
reason why spermatozoids occur in Ginkgo and Cycas but not in 
other Gymnosperms, so long as the motile elements shall not have 
been discovered in such Gymnosperms, where the relation of the tube 
to the archegonia is different from that of our plants. 
Since Hofmeister’s classical researches, we know that there is no 
sharp boundary between the higher Cryptogams and the Phanerogams. 
On the other hand, however, it was generally accepted as a fact without 
exception, that in the former fertilization takes place by spermatozoids, 
while in the latter it occurs by pollen-tubes, so that we must have 
concluded that in this respect only there exists a sharp boundary 
between these two great groups of plants. But now this boundary 
has been broken down, and therefore the truth of the fact that both 
are very intimately connected becomes more and more prominent. 
Finally we have to draw the attention of our readers to the fact that 
Hofmeister long ago stated his supposition that in the pollen-tube of 
Conifers spermatozoids would be found to be produced.. Pringsheim 
also repeatedly stated his opinion that they must be present in the 
pollen-tube of Phanerogams. The supposition of these great botanists 
has now been proved to be partly right. 
S. IKENO and S. HIRASE, 
Tokyo. 
