112 LIVERPOOL BIOLOGICAL SOCIETY. 
controversy to the conclusion that all these higher develop- 
ments have had their first origin in the union of two 
motile flagellate masses of protoplasm between which 
there is no apparent differentiation; but that very early as 
we ascend in the evolutionary scale, these two masses of 
protoplasm exhibit differences which become gradually 
more and more marked as they develop into what we 
term male and female cells; the latter very soon losing 
their flagellate character, becoming quiescent, and increas- 
ing in size; the former going through the various stages 
of a biflagellate zoogamete indistinguishable from a zoo- 
spore, and the multi-flagellate antherozoid of the higher 
Cryptogams ; and being finally replaced by the pollen-gram 
of Flowering Plants, with its power of putting out pollen- 
tubes. 
Are we not then justified in regarding every process of 
fertilisation simply as a modification of a process of 
nutrition, the conveying to a potential germ of some 
property which it has not derived from its own ancestors, 
but which gives it greater completeness and power of 
developing into a new individual? In connection with 
this view it is interesting to observe that, although the 
flagellate condition is especially characteristic of cells 
which are concerned directly with a process of reproduc- 
tion, this is not universally the case; instances are known 
in which the functions of flagellate cells are purely nutri- 
tive. It would lead me beyond the limits of my present 
subject to speak in detail of the remarkable phenomena 
- connected with the uniflagellate swarm-cells of the 
Myxomycetes, which display extraordinarily active powers 
of ingestion and digestion of both fluid and solid materials, 
while in their motile condition before coalescing mto a 
plasmode. On this subject I can only refer to a valuable 
paper by Lister recently contributed to the Linnean 
G 
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