544 
APPENDIX. 
[B, 
funiculus umbilicalis ; at the same time he seems to admit 
the existence of the aperture in the coat. 
In 1745, Needham*, and in 1770, Gleichent, adopt the 
hypothesis of Morland, somewhat modified, however, as they 
consider the particles in the grains of Pollen, not the grains 
themselves, to be the embryos, and that they enter the 
ovula by the umbilical cord. 
Adanson, in 1763 J, states the Embryo to exist before 
fecundation, and that it receives its first excitement from 
a vapour or aura proceeding from the Pollen, conveyed to it 
through the trachese of the style, and entering the Ovulum 
by the umbilical cord. 
Spallanzani §, who appears to have carefully examined the 
unimpregnated Ovula of a considerable variety of plants, 
found it in general to be a homogeneous, spongy, or gela- 
tinous body ; but in two Cucurbitaceae to consist of a nucleus 
surrounded by three coats. Of these coats he rightly sup- 
poses the outermost to be merely the epidermis of the middle 
membrane or testa. Of the relative direction of the testa and 
inner coat in the two plants in question he takes no notice, 
nor does he in any case mention an aperture in the Ovu- 
lum. 
Gsertner, who, in the preface to his celebrated work, dis- 
plays great erudition in every branch of his subject, can 
hardly, however, be considered an original observer in this 
part. He describes the unimpregnated Ovulum as a pulpy 
homogeneous globule, whose epidermis, then scarcely dis- 
tinguishable, separates in a more advanced stage, and be- 
comes the testa of the seed, the inner membrane of which is 
* New Microscopical Discoveries, p. 60. 
t Ohserv. Microscop. p. 45. 61. § cxviii. 
J Fam, des Plant, tom. i. p. 121. 
§ Fisica Anim. e Vcget. tom. iii. p. 309 — 332. 
