158 DEVELOPMENT OF THE OVULUM 
If it be found never to be obliterated, its situation will at 
once point it out, and I think it might be affirmed, that in 
all cases the coat in contact with, or next to the embryo, is 
derived from this sac. 
On this membrane Mr. Brown observes ‘‘in general the 
amnios, after fecundation, gradually enlarges, till at length it 
displaces or absorbs the whole substance of the nucleus, 
containing in the ripe seed, both the embryo and albumen, 
where the latter continues to exist." Nothing can be more 
clear or more true than this. 
Brongniart describes the embryonary sac as disappearing 
in all exalbuminous plants, either completely or by uniting 
with the parenchyma of the nucleus, and forming the inner 
membrane ; and he figures (See Memoir Pl, 42, fig. 1,) the 
immediate envelope of the seed as being derived from the 
nucleus. 
M. Brongniart's opinion corroborates the truth of Mr. 
Brown's statement. 
At page 92, however, this author refers to the difficulty 
of examining the embryonary sac before impregnation, on 
account of its smallness. There is some difficulty in recon- 
ciling this to his statements elsewhere. 
I have already alluded to the additional organ described 
by Brongniart as forming a communication between the 
apex of the embryonary sac, and that-of the nucleus. And if, 
as I believe it will be found to be the sac under consi- 
deration, (and which is frequently, nay perhaps generally, 
formed after fecundation,) it is obvious that this idea is unten- 
M. Mirbel's quartine is obviously the amnios of Mr. Brown, 
and the embryonary sac of M. Brongniart. 
As in Cicer arietinum, and Phaseolus coccineus, and Lupi- 
nus varius. 
It would not be difficult to shew that Mirbel has more than 
once confounded his quartine with his quintine, and vice 
versa. (See his Figures etc. of Tradescantia.) And even oc- 
casionally with the nucleus, as in Myrica pensylvanica, and 
Quercus Robur. In Polygonum tataricum his quintine is 
