RUPPIA. 199 
tration, for the nucleus presents none of those indications by 
which its apex is in most other ovula or seeds so easily re- 
cognised, on the contrary, its surface is homogeneous and equal 
throughout. But it may be inferred that it does not; for 
although one instance has been adduced in which the radicle 
does not correspond to the opening in the teguments, I know 
of none in which it does not correspond to the apex of the 
nucleus, for even in cases where it is formed externally to the 
nucleus, it agrees in direction with this body. 
The ovulum has I think otherwise the ordinary structure, 
differing only in the very large size of the cell from which 
the embryo is developed, and to which, under some modifica- 
tion or another it is always attached. In supposing this glo- 
bular body to be the footstalk of the embryo, I am guided en- 
tirely by analogy, for I have not been able to separate the em- 
bryonary sac, which I consider to occupy closely the more 
transparent part of the young seed. Of such extreme tenuity 
and intimate adherence, examples are by no means wanting, 
but it would be contray to all analogy to assume that the 
embryo is formed outside the embryonary sac. The direction 
of the young radicle does not appear to be otherwise cons- 
tant, that it is not always in the axis of the ovulum, but is 
generally inclined to one side or other. I thought at 
one time that it was generally inclined to the foramen, but I 
am not disposed to say that it is constantly so, indeed the 
_ cavity of the embryonary sac is so large, and its contents so 
aqueous that very slight pressure necessarily consequent on 
dissection may cause a change. 
The cotyledone is not tardy in making its appearance, 
its direction is oblique with regard to the radicle, and it as- 
sumes its subsequent recumbent position owing to the resi- 
stance its meets on its reaching the upper part of the cavity 
of the sac; and when the embryo is half developed, the 
existence of the plumule may likewise be ascertained. 
The radicle always maintains its original direction which 
is that of the ovulum before impregnation. That part of 
