540 
APPENDIX. 
[B. 
the function of the Chalaza in seeds * ; and sometime before 
the publication of the observation now quoted, I had ascer- 
tained that in Phsenogamous plants the unimpregnated Ovu- 
lum very generally consisted of two concentric membranes, 
or coats, enclosing a Nucleus of a pulpy cellular texture. 
I had observed also, that the inner coat had no connexion 
either with the outer or with the nucleus, except at its 
origin; and that with relation to the outer coat it was 
generally inverted, while it always agreed in direction with 
the nucleus. And, lastly, that at the apex of the nucleus 
the radicle of the future Embryo would constantly be found. 
On these grounds my opinion respecting the Embryo of 
Cephalotus was formed. In describing the Ovulum in this 
genus, I employed, indeed, the less correct term “ saccu- 
lus,” which, however, sufficiently expressed the appearance 
of the included body in the specimens examined, and served 
to denote my uncertainty in this case as to the presence of 
the inner membrane. 
I was at that time also aware of the existence, in several 
plants, of a foramen in the coats of the Ovulum, always 
distinct from, and in some cases diametrically opposite tOj 
the external umbilicus, and which I had in no instance found 
cohering either directly with the parietes of the Ovarium, 
or with any process derived from them. But, as I was then 
unable to detect this foramen in many of the plants which I 
had examined, I did not attach sufficient importance to it; 
and in judging of the direction of the Embryo, entirely de-s 
pended on ascertaining the apex of the nucleus, either 
directly by dissection, or indirectly from the vascular cord 
of the outer membrane : the termination of this cord afford^ 
ing a sure indication of the origin of the inner membrane,,^ 
* Linn, Soc, Transact, x, p. 35. 
