F. E. Fritsch 
178 
terrestrial and freshwater habitats and should be so poorly represented 
in the sea. These are facts which speak for a common origin of 
freshwater and terrestrial Green Algae and the higher land-plants 
and, since evidence of reduction in Green Algae as a whole cannot 
be admitted, it strikes at the root of Church’s assumption. 
At this point reference may be made to the other aspect of 
Church’s theory, viz. the mode of transmigration. According to the 
present-day geological view there were both land- and sea-surfaces 
from the earliest times. If that was so, there was no doubt evapora¬ 
tion from the surface of the sea and subsequent atmospheric pre¬ 
cipitation, which will have led to the formation of rivers and other 
large bodies of freshwater. We cannot preclude the possibility of an 
independent origin of green plant-life in such pieces of freshwater 
and of the ancestors of the higher plants never having been in the 
sea at all. Invasion of the sea by way of rivers on the part of a few 
freshwater Green Algae is not an impossibility and in the case of 
forms like Cladophoraceae and Ulvaceae even plausible in view of 
their present-day distribution. I hold no brief for either view, but 
consider that both possibilities must be reckoned with. 
East London College, 
July , 1921. 
