Botany.] 
NATURAL HISTORY. 
.047 
the vegetable Embryo*, in which he describes the ovulum 
before fecundation as having two coats ; but of these, his 
inner coat is evidently the middle membrane of Grew, the 
chorion of Malpighi, or what I have termed nucleus. 
In 1822, Mons. Dutrochet, unacquainted, as it would 
seem, with the dissertation of Professor Treviranus, pub- 
lished his observations on the same subject f. In what 
regards the structure of the ovulum, he essentially agrees 
with that author, and has equally overlooked the inner 
membrane. 
It is remarkable that neither of these observers should 
have noticed the foramen in the testa. And as they do not 
even mention the well-known essays of MM. Turpin and 
Auguste de St. Hilaire on the micropyle, it may be presumed 
that they were not disposed to adopt the statements of these 
authors respecting it. 
Professor Link, in his Pkilosophia Botanica, published 
in 1824, adopts the account given by Treviranus, of the 
coats of the ovulum before impregnation I; and of M. Turpin, 
as to the situation of the micropyle, and its being the cicatrix 
of a vascular cord. Yet he seems not to admit the function 
ascribed to it, and asserts that it is in many cases wanting §. 
The account which I have given of the structure of the 
vegetable ovulum, differs essentially from all those now 
quoted, and I am not acquainted with any other obser- 
vations of importance respecting it. 
Of the authors referred to, it may be remarked, that those 
who have most particularly attended to the ovulum ex- 
* Entwick. des Embryo im Pflanzen-Ey. 
Mem. du Mus. d'Hist. Nato tom. viii. p. 241, et seq. 
$ Elcm. Philos. Bot. p. 338. 
§ /c/. p. 340. 
2 N 2 
