548 
appendix. 
[B. 
ternally, have not always examined it at a sufficiently early 
period, and have confined themselves to its surface : that 
those who have most minutely examined its internal struc- 
ture, have trusted too much to sections merely, and have 
neglected its appearance externally: and that those who 
have not at all examined it in the early stage, have given 
the most correct account of its surface. This account was 
founded on a very limited observation of ripe seeds, gene- 
ralized and extended to the unimpregnated ovulum, in con- 
nexion with an hypothesis then very commonly received: 
but this hypothesis being soon after abandoned, their state- 
ment respecting the ovulum was rejected along vdth it. 
In the ovulum of Kingia, the inner membrane, with re- 
lation to ihe external umbilicus, is inverted ; and this, as 
I have already observed, though in direct opposition to 
M. Turpin’s account, is the usual structure of the organ. 
There are, however, several families in each of the two 
primary divisions of phrenogamous plants, in which the 
inner membrane, and consequently the nucleus, agrees in 
direction with the testa. In such cases the external um- 
bilicus alone affords a certain indication of the position of 
the future embryo. 
It is an obvious consequence of what has been already 
stated, that the radicle of the embryo can never point di- 
rectly to the external umbilicus or hilum, though this is said 
to be generally the case by the most celebrated carpologists. 
Another observation may be made, less obviously a con- 
sequence of the structure described, but equally at variance 
with many of the published accounts and figures of seeds, 
namely, that the radicle is never absolutely enclosed in the 
albumen ; but, in the recent state, is either immediately in 
contact with the inner membrane of the seed, or this con- 
tact is established by means of a process generally very 
