il 
from which, however, it is very different, the latter being 
plentiful both in Norfolk Sound and here. I say nothing of 
the aspect of the plant, which Agardh has tolerably well 
described; but shall only state that the internal substance 
of the two is perfectly heterogeneous. In the American 
species, the sack is round, the membrane which constitutes 
it very thin; and if this sack be full of sea-water, the con- 
tents, on its being pressed with the finger, escape forcibly 
through a number of pores on all sides: while in most of 
the individuals which occur here, the sack collapses laterally 
like parchment, and the little water which it contains is 
not sent out to any distance by compression. The colour 
of the sack in this kind is always red. : 
* [ must here take notice of another species, most nearly 
related to the first; in which the base of the sack is prolonged 
into a point, whilst in the other kinds it is constantly 
rounded off. I found the American species only on F. vesi- 
culosus, which occasionally grows here on such stones as are 
periodically washed by the tides. "To conclude, I farther 
mention that at Sitcha, I gathered still another saccate kind, 
inhabiting F. Larix. Iam, however, yet doubtful if it properly 
belongs to the Fuci, as its sack shows a tendency to pass into 
a gelatinous membrane. F. digitatus occurs here in various 
shapes; a dozen different aspects of it now lie before me, 
which merge imperceptibly into one another. Whether 
Agardh's species, Laminaria reniformis, brevipes, and even 
Belvisii, have been accurately examined, is doubtful. The 
fructification is in darker, more elevated, and sinuated 
portions of the frond. The F. evanescens, Agardh, which 
Chamisso gathered here, I can consider as nothing more 
than a variety of F. vesiculosus, although it is the only Fucus ` 
occurring here of this form. I have sought everywhere, and 
in vain, for F. Myrica; and I am still doubtful as to F. 
