ion takes
place through a cord or fasciculus of vessels entering the outer coat of
the ovulum, at a point distinct from, but at the period of impregnation
closely approximated to the umbilicus, and to the cicatrix of this cord,
which itself is soon obliterated, he gives the name of Micropyle: that
the ovulum has two coats, each having its proper umbilicus, or, as he
terms it, omphalode; that these coats in general correspond in direction;
that more rarely the inner membrane is, with relation to the outer,
inverted; and that towards the origin of the inner membrane the radicle
of the embryo uniformly points.

(*Footnote. Annal. du Mus. d'Hist. Nat. 7 page 199.)

It is singular that a botanist, so ingenious and experienced as M.
Turpin, should, on this subject, instead of appealing in every case to
the unimpregnated ovulum, have apparently contented himself with an
examination of the ripe seed. Hence, however, he has formed an erroneous
opinion of the nature and origin, and in some plants of the situation, of
the micropyle itself, and hence also he has in all cases mistaken the
apex for the base of the nucleus.

A minute examination of the early state of the ovulum does not seem to
have entered into the plan of the late celebrated M. Richard, when in
1808 he published his valuable and original Analyse du Fruit. The ovulum
has, according to him, but one covering, which in the ripe seed he calls
episperm. He considers the centre of the hilum as the base, and the
chalaza, where it exists, as the natural apex of the seed.

M. Mirbel, in 1815, though admitting the existence of the foramen or
micropyle of the testa,* describes the ovulum as receiving by the hilum
both nourishing and fecundating vessels,** and as consisting of a uniform
parenchyma, in which the embryo appears at first a minute point,
gradually converting more or less of the surrounding tissue into its own
substance; the coats and albumen of the seed being formed of that portion
which remains.***

(*Footnote. Elem. de Physiol. Veg. et de Bot. tome 1 page 49.)

(**Footnote. Id. tome 1 page 314.)

(***Footnote. Id. loc. cit.)

In the same year, M. Auguste de Saint Hilaire,* shows that the micropyle
is not always approximated to the umbilicus; that in some plants it is
situated at the opposite extremity of the ovulum, and that in all cases
it corresponds with the radicle of the embryo. This excellent botanist,
at the same time, adopts M. Turpin's opinion, t