417 
- process is to prepare any impregnating vapour, or, 
more probably, to rarefy air for the purpose of in- 
flation, I have not been able to discover. In the 
old bladders little traces remain of it, when the 
skin (as is the case in #. nodosus) acquires the thick- 
ness of sole-leather. I find likewise the inside of 
the pod of F. szlzquosus to consist of a curious 
branched process, extending in all directions, and 
not simple threads stretched across, as I had de- 
scribed it, p. 9. I have likewise discovered the 
fructification of /. digitatus and Polyschides to be 
an imbedded oval bladder, and not asuperficial one, 
as I had described it; covered with a tender pellicle. 
I have not yet seen it in maturity. A fragment. of 
F’. palmatus in fructification was thick set with 
conical protuberances, perforated at the summits, 
with the seeds imbedded in the internal substance. 
This mode is very similar to that of F. vesiculosus, 
&c., excepting that in the latter, nature has set 
apart a fruit. The powers of my glasses go as far 
as to discover the internal structure of Ulva umbz- 
licalis, the thinnest and most membranaceous of 
sea plants; and I have discovered small dark per- 
forated granules, which are undoubtedly the seeds. 
I shall take the liberty of inclosing two or three 
new species or varieties of sea plants to add to your 
collection ; and having drawn up a paper on the 
Herniaria glabra, in which you will discover many 
errors of the early writers rectified, and a descrip- 
tion more at large than I have met with, I shall beg 
the favour of you to present it to the Society. 
I beg leave to subscribe myself, Yours, &c. 
J. STACKHOUSE. 
VOL. I. 2 
