Limerick: W. H. Harvey. Near Ballycastle: Mr. D.
Moore. Roger’s Tower ou Castle an Dinas, near Gul-
va ll; and Bosigran Castle, near Morvah; in both places
on g ran ite : Mr. Bon'er. Dublin Bay : Mr. Moore.
On damp shaded walls, on the g ro u n d ; frequent, near
Tunbridge Wells: Mr. Jenner. Walls of Chesterton
church, near Cambridge: Rev. Prof. Henslow.
Having carefully examined numerous specimens which have
been sent me under the names of Ulva crispa and Ulva fu r -
furacea, and not being able to detect the slightest difference In
the microscopic characters of these, I do not hesitate to unite
the two supposed species.
The specific denominations of ci'ispa and furfuracea are
both well expressive of the appearance of this species: the cells
are densely crowded together in the frond, so as indeed to
leave very narrow interspaces between the groups of cells,
which arc usually composed each of about sixteen cells,
disposed in fours, and which from the compression one against
the other are rendered somewhat angular. The different
groups of cells are not disposed usually in linear series.
3. U lva calophylla Spreng.
Plate L X X V I I . Fig. 1.
Char. Frond densely tufted, plane, linear, ligulate, attenuated
at base, often stipitate, longitudinally striate, each
stria marked with a series o f bi-quaternate granules.
Hook. Brit. Flor. vol. ii. p. 312. Bangia colophylla Carm.,
in Grev. Crypt. FL, t. 220.
Hab. On damp stones, rocks, &c.; Lismore Island,
Appin : Captain Carmichael. Near Limerick : W. H.
Harvey. D u b lin : Mr. Moore and Dr. G. J. Allman.
North of Ire lan d : Mr. D. Moore. Oswestry : Bev. J.
Salwey.
“ This forms a bright green thin stratum. Frond minute,
three or four lines long, linear, strap-shaped, obtuse, tapering
at base, or suddenly contracted into a cylindrical stipes, much
waved and curled, very variable in breadth. Granules quaternate,
closely covering the frond, set in longitudinal lines, of
which two or more (sometimes half a dozen) form the breadth
of the frond ; interstices colourless.” — Harv.
Kiitzing makes a new genus for this species under the
name of Prasiola.
4. U lva binalis Hass.
Char. Cells large, in twos.
I have not studied this species with sufficient attention to
pronounce decidedly whether it is distinct or not ; the arrangement
of the granules by twos would seem, however, to
be remarkable, and to render it very probable th a t it really is
so. This species would appear to be referred to in the following
remarks of Vaucher’s “ Hist, des Conf.” p. 238. “ I t
is not impossible but tha t other species of freshwater Ulvce
exist independently of those which I have described. I have
myself met with some others which have appeared to me to be
different from the two first ; one in particular, the grains of
which were disposed two by two, and not four by four ; but I
pass them by under silence, because I am not assured whether
they are species or only varieties.”
40. M E R ISM O P ED IA .
Char. Frond increasing hy spontaneous division, laminar,
quadrangular.
Derivation. From gspiagos, a division, and irsSiov, a
fetter or chain.
1. Merismopedia punctata Meyen.
P late L X X X IV . Fig. 6.
Char. “ Green, corpuscles imbedded in a crystalline membrane,
and nearly the o f a millimetre in size, polypary,
quadrangular, flattened, sometimes twice as broad as long,
equalling from the to ^ o f a millimetre, and containing
sixteen simple corpuscles, either binary or quaternary.” —
Ehr.