10. H æmatococcus fkustulosus Harv.
Plate L X X X I . Fig. 1.
Char. Crust widely spreading, friable, dark grey. Cells large,
roundish, containing numerous, very minute, scattered
granules.
Palmella frustulosa Carm., MSS. cum icone. Hæmatococcus
frustulosus Harv., in Hook. Br. Fl. p. 395. ; also in
Manual, p. 181.
Hah. On irrigated cliffs, perennial, Appin ; Capt. Carmichael.
Capt. Carmichael thus briefly describes this fine species : —
“ It occurs in the form of a greyish black fragmentary scurf
On the slightest pressure it separates into corpuscles of various
forms, hut mostly spherical, hyaline: under the microscope,
surrounded hy a membranous envelope, and including
several granules.”
The granules are very minute, spherical, not usually surrounded
by vesicles, and very numerous, the larger cells enclosing
as many as one or two hundred granules.
11. H æmatococcus arenakius Dass.
Plate L X X V I . Fig. 10.
Char. Cells spherical, rather small, containing spherical
green granules, varying in number from one to ten, but
usually there are fiv e or six.
Hab. Tunbridge Wells Common : Mr. Jenner.
This species approaches rather closely to the preceding, but
yet may be easily distinguished from it. The cells or fronds
of H. arenarius are much smaller, contain fewer granules,
although these are larger than those of H. frustulosus.
*** Granules frequently binate or quaternate.
The granules in all the species of the genus Hæmatococcus
are increased by division, the division not usually extending
331
to the outer membrane. The cells, the youngest o f all, contain
but a single granule: as the developement proceeds, this
becomes divided into two other granules, and these are again
subdivided, and so on the process of multiplication proceeds,
in some cases, as in H. sanguineus and H. frustulosus, to a
much greater extent than in other species.
12. H æmatococcus binalis Hass.
Plate L X X X I I . Fig. 2.
Char. Cells large, elliptical, green, each containing mostly two
semi-elliptical granules.
Pleurococcus thermalis ? Menegh., loc. cit. t. iv. fig. 3.
Hab. Cheshunt ; A. H. H. Aberdeen, mixed up with
other Algæ : Dr. Dichie.
This species is very distinct. Some of the cells contain
but a single granule, others two, and these are by far the
most numerous ; others again, four granules. The species I
suspect is by no means uncommon.
It is not unlikely that this Is an appendaged species.
13. H æmatococcus furfuraceus Hass.
Plate L X X X I I . Fig. 4.
Char. Cells small, spherical, or somewhat angulated. Granules
often associated in pairs.
Palmella furfuracea Berk., Glean. Alg. p. 18. t. 5. f. 3. P.
furfuracea Harv., in Manual, p. 178.
Hah. Forming a thin mealy stratum of a light yellowish
green, on the walls of a large frame at Milton, Northamptonshire
: Rev. M. J. Berkeley. Limestone rocks,
CO. Antrim : Mr. Moore.
“ Fronds aggregate, diffuse. Irregular, granulated, rather
rigid, under the knife, falling down into a mass o f minute