136 DEVELOPMENT OF THE OVULUM 
I have not observed any appearance of secreting surface 
at the apex, which is in all generally unequal. Neither 
have I seen its occasional projection beyond the orifice of 
the outer coat. Its cohesion with that coat has escaped me. 
The statement of the ovula of Cycadez consisting of a nu- 
cleus and one coat only, is an oversight. Cycas merguien- 
sis has two, cohering intimately ; Agathis is also an instance 
of the correctness of this view. 
This celebrated Botanist can only have examined certain 
stages of the ovula of Gnetum, to which he attributes three 
envelopes, considering as two the coats of the nucleus, but 
not referring the third, or outer to any thing. I hope I un- 
derstand rightly: to prevent mistake, I quote his words— 
** In Ephedra, indeed, where the nucleus is provided with 
two envelopes, the outer may perhaps be supposed rather 
analogous to the calyx, or involucrum of the male flower, 
than as belonging to the ovulum, but in Gnetum, where the 
envelopes exist, two of these may, with great probability, be 
regarded as coats of the nucleus." 
Mr. Lindley considers the outer, concerning which Mr. 
Brown is silent, to be analogous to a carpellum. 
Historical Notes. 
For the history of the ovulum, refer to Mr. Brown's cele- 
brated Memoir on Kingia; to which the first accurate 
knowledge of this important organ is to be attributed. 
Flinder's Voy. 11. p. 681, and Linn. Soc. Trans. xii. 
p. 136, Mr. Brown refers to some other of his publica- 
tions with reference to the state of his knowledge at that 
time, but which he informs us had been overlooked by all 
Botanists. 
With regard to the various and mistaken opinions referred 
to in the historical account I may observe, that they all arose 
from an error but too frequent up to a very recent period, 
viz. a disposition to convert a science of observation into 
one of speculation. As a proof of this, we find that the 
