Notes. 
376 
These three cells formed by the division of the oospore seem to me 
to correspond and be homologous with the sporophore of Coleochaete , 
and the three cells individually to the spores, one of which produces 
nothing ; of the other two one germinates to produce the proembryo, 
and the other some root-hairs, which may be looked upon as an 
abortive attempt to produce another proembryo. The morphological 
position of the proembryo would then be that of an embryonic stage 
in the development of the oophore corresponding to a certain extent 
with the protonema of true Mosses. 
I should therefore regard Chara as being in all probability 
connected with the Florideae ; such a view is also to be supported on 
anatomical grounds, the cortex of Chara resembling nothing so much 
as the cortex of many Florideae. These, views of the systematic 
position of Chara , and also the interpretation of its life-history given 
above, would receive much support, if they are confirmed, from the 
observations of Sirodot 1 on Batrachospermwn and Chantransia. 
In the course of the last few years some botanists have assumed 
that it was not possible to form homologies and make comparisons 
between the structures of the sporophore of the Vascular Plants and the 
oophore of the Muscineae and the large vegetative body of some of 
the Melanophyceae in which there is only an oophore. 
The full reason why such comparisons as those just alluded to are 
not allowable has not, I think, yet been fully stated. It is this that 
in the light of what has gone before I hope to make clear. 
It is perhaps unnecessary to say that only those organs are con- 
sidered homologous with one another which can be shown to be 
derived from a common ancestor quite regardless of their functions, 
as the wing of a bird is homologous with the fore-foot of any quadruped 
or the arm of a man, but not homologous with the wing of an insect, 
the relation in that case being one of analogy. 
Now according to the view that Pringsheim took that both sporo- 
phore and oophore were derived from a common ancestral form 
which was both sexual and asexual, a certain amount of homology 
might be supposed to exist between the oophore and sporophore ; 
but even then it is questionable if there would be any homology 
between organs developed in each generation after their complete 
separation from one another by differentiation. 
1 Sirodot, Sur les Batrachospermes, 1884; sur les Lemaneacees, Ann. Sci. Nat. 
ser. 5, t. xvi, 1872. 
