or olive green, formed by the plant here figured, which adheres
so closely to the surface of the rock that it can only be removed
in fiakes by scraping with a knife. It was first noticed on the
shores of Norway and the Foeroe Islands, and has since been
found in many places along the Atlantic coasts of Europe, and
probably exists in many others where hitherto it has been overlooked.
I have vainly examined numerous specimens in search
of the fructification, described by Capt. Carmichael, who discovered
it after the examination of more than a hundred. The
large cell near the middle of the filaments, which I find on my
specimens, has not been noticed by other authors who have described
or figured the plant, yet it constitutes a very remarkable '
feature. Possibly it may not be always so obvious. It is hard
to say whether it has any connection with the fructification, or
what peculiar function it may perform in the economy of the
plant, but it appears to have at least an analogical resemblance
to what are called connecting cells in Sphceroeijga, the office of
of which is equally doubtful. It can have no relation to the
spores described by Carmichael, which would appear to be
formed from an alteration of the whole filament; not from a
solitary joint. Whether it undergoes any change at a later
period has not been observed.
Tig. 1. Cruokia pellita, groivmg on a piece of rock -.— o f the natural size. 3
Portion of a vertical section of the stratum. 3. Tuft of filaments removed
and opened. 4. Some of the filaments separated more or le.