SOME PROBLEMS OF REPRODUCTION. . 89 
there is no question of giving a mystical significance to this 
‘excretion process.” 
(4) The Lower Subbasal and the two Basal Cells 
lie huddled and inert at the base of the embryo-sac, as 
“Antipodal cells,” and finally disappear in the growing 
endosperm. 
The homologies of these structures are somewhat ob- 
scure, but the following explanation may be tendered as a fair 
one : 
(1) The four cells of the form N? correspond to prothal- 
lial cells of a Cryptogam or Gymnosperm ; cells which we 
know form the common initials of both archegonium-wall (or 
neck at least) and oogonium. 
(2) The Apical cell (N*a) divides to form an archegonium 
of two neck-cells only, without any oogonium (such an arche- 
gonial neck of two cells is found in Cycads). 
(3) The Subapical cell (N’sa) divides into a superposed 
pair of which the Upper is the oosphere, of whose sig- 
nificance as a gamete there can be “no possible doubt what- 
ever.” 
(4) The Lower Subapical cell (N*lsa) is that which con- 
jugates with the Upper Subbasal (N®*usb) ; as a consequence 
the cell produced by their fusion rejuvenesces, and by its 
repeated bipartition forms the endosperm. This structure is 
comparable to a thallogenous plant of low organisation and 
limited life; the endosperm-cell that produces it must be 
regarded as a zygote, and the two cells that unite to form this 
zygote are necessarily gametes, whose close kinship, though 
the most distant possible under the circumstances, may influ- 
ence the low organisation and limited life of their zygote.! 
Thus the subapical cell producing by bipartition two gametes 
is a gametogonium ; or we may go further and identify it with 
an initial cell, producing an archegonium without a neck, and 
reduced to the oogonium. Of the two gametes formed by the 
1 This important identification of the endosperm-cell as a zygote was first 
made out by Professor Le Monnier, of Nancy, in an unpretentious little note 
in ‘ Morot’s Journal de Botanique,’ vol. i, p. 140 (June, 1887). 
