No. 457.] EMBRYO OF THE ANGIOSPERMS. 23 
two cotyledons into a single member. Thus while the relative 
value of the cotyledons in the two classes needs no further dis- 
cussion at this time, we have yet to choose between the hypoth- - 
esis elaborated by Miss Sargant and the one suggested by the 
writer. 
It is obvious that the anatomical and morphological evidence 
collected by Miss Sargant can as readily be interpreted in sup- 
port of the writer's hypothesis as the one brought forward by 
herself. It can quite as well be interpreted as showing a transi- 
tion from the monocotylous to the dicotylous condition by a 
bifurcation of the cotyledon, as demonstrating a reduction from 
the dicotylous to the monocotylous condition through a fusion of 
two cotyledons. It can be read forward as well as backward. 
Progression in evolution is quite as plausible as retrogression, 
yet Miss Sargant hopes to convince her readers with the fol- 
lowing unique argument: “To conceive of steps by which two 
separate cotyledons should gradually unite is easier than to 
imagine a single cotyledon splitting into two similar members as 
suggested by Mr. H. L. Lyon." 
While Miss Sargant is able to cite some thirty dicotyledonous 
seedlings as having their cotyledons partially or completely 
united into a single member, one might easily mention a hundred 
dicotyledonous seedlings having their cotyledons deeply emargi- 
nate, bifid or even bipartite. Then cotyledons deeply three- 
lobed, four-lobed, and five-lobed are not unknown. In various 
species of Acer, seedlings with three and four distinct cotyledons 
are of frequent occurrence. Pittosporum crassifolium produces 
three or four cotyledons quite as often as two, while Auytsia 
floribunda habitually produces embryos with three or four coty- 
ledons. Would the writer propound an inconceivable hypothesis 
were he to suggest that in these dicotyledons the variously lobed 
and polycotyledonous conditiogs had arisen through a splitting of 
cotyledons ; or must he adopt that *easier" line of reasoning 
and maintain that the polycotyledonous condition is the more 
primitive, and that the dicotyledonous condition has been arrived 
at through a reduction by the gradual union of the many mem- 
bers into two? All morphologists will affirm that this lobing of 
the cotyledons has resulted through adaptation to the various 
