^ The foregoing life-history is somewhat abridged from the acoonnt
given by Braun (“ Eejnvenesoenoe,” pp. 206-214), and for farther details
the reader is referred to the Memoir by Plotow (“ Nova Acta
Natura Cnriosorum,” Vol. xx. p. 11), and that by Cohn (translated in
“ Memoirs ” by the Kay Society, 1853), which will furnish all that can
be required, and are really exhaustive. For remarks on an Amæboid
condition see paper by T. Charters White in the “ Journal of the
Qnekett Microscopical Club ” for 1879.
Plate X X I . Jig. 1. a, still cells X 400; b, green cell with chlorophyll
vesicle, and reddish nucleus ; o, a cell which had been dried six
years, undergoing segmentation after revival ; d, completed division ;
e, division into four ; /, naked green zoospore ; g, encysted zoospore ;
h, primordial cell, commencing division iu two ; i, encysted zoospore,
which has deliquesced ; j, primordial cell dividing in four ; k, encysted
zoospore in still condition ; I, division of still cell iuto 8 cylindrical
zoospores ; m, escaped zoospore ; n, division of encysted cell into 4 ;
0, division into 8 ; p, division into 32 ; q, zoospores from the latter form
escaped from mother-oell ; r, large red still cell dividing into segments ;
s, red encysted cell ; t, yellow-green still cell. All after Cohn.
C h lam y d o co c cu s n iv a lis . Br. Bejuv.p.206.
Cells globose, red, at first with a hyaline border, which is the
thickened epispore, which gradually disappears with age.
S i z e . Cells ’Ol-'OS mm. diam.
Eab. Alg. Eur. iii. 93.
Hoematococcus nivalis, Ag Icon. Alg. t. 31.
Protococcus nivalis, Ag. Supp. p. 13. Hook. Eng. FI. v.
p. 395. Mackay Hibern. p. 246. Hass. Alg. p. 385, t. 83, f. 2.
Harv. Man. p. 182. Grev. Sc. Crypt. FI. t. 231.
Palmella nivalis, Hook, in Pa rry’s Voy. App. p. 328.
Tremella nivalis, Brown, in Boss Voy. Supp. p. 44.
Uredo nivalis, Bauer. Journ. Sci. and' A rt vii. p. 222, t. 6.
On snow and wet rocks, &c.
Probably not specifically distinot from Chlamydococcus pluvialis. For
the history of this minute plant, long known as “ Bed Snow,” consult
“ Greville’s Scottish Cryptogamio Flora,” Vol. iv. plate 231. The interesting
observations by Agardh and others, there detailed, are too long
for quotation here.
Introduced to the notice of botanists in this country on the return of
Capt. Boss from Baffin’s Bay, where it was found extending for some
miles, it was regarded by Bauer as a fungus, by Eobert Brown as an
Alga, and by Baron Wrangel as a Lichen. Agardh first included it in
Algæ, nnder the name of Protococcus nivalis.
I t has beeu fonnd in this country “ on the borders of the lakes of
Lismore, spreading abundantly over the decayed reeds, leaves, &c., at
the water’s edge, bnt in greater perfection on the calcareous rooks within
the reach of occasional inundation, more or less perfect at all seasons of
the year.”—Carm. Also in Ireland.
Plate X X I. Jig. 2. a, still cells X 400 ; h, cell divided in two; c, cell
divided in four ; d, advanced stage of subdivision in fonr ; e, encysted
zoospore ; /, free zoospore ; g, resting cell.
Gbnus 38. CHLAMYDOMONAS. Elwl. (1833.)
Macrogonidia ovate or oblong-rounded, green, delicately
granulated, involved in a ra th e r narrow hyaline tegument
frontal extremity very obtuse, or somewhat truncate, with a
contractile vacuole, and two cilia ; posterior extremity with a
large chlorophyllose vesicle, and with or without a red lateral
spot. Microgonidia arising from repeated division of the cytio ■
plasm of the macrogonidia, oblong or ovate, numerous, pale
green or yellow, becoming brownish. Tranquil oospores globose,
red or brownish, contents firm, colourless, hyaline.
“ Chlamydmnonas is distinguished from Chlamydococcus by the closely
applied membrane (not standing away from the contents) of the old
swarming cells, also by the absence of the little staroh-vesioles in the
interior, while, however, as is usnal in most of the Balmellaceai, a single
large ‘’chlorophyll utricle ’ (starch utricle ?) exists in the interior.
There is no central red nucleus, as in the gonidia of Cklamydococcns,
but some species have a parietal red spot. The motion is affected by
two cilia, as in Chlamydococcus. As in that genus, there is a growth of
the gonidia during ‘ swarming,’ which lasts over the day and night.
There is also a formation of microgonidia. The species of this genus
are doubtless very numerous, but the distinotion of them among them,
selves, as well as from the swarming cells of many other Algie, is yery
difficult without a complete acquaintance with the history of their lives.
The species Chi. obtusa, occurs in the Rhine valley, near Freiburg, in
sand pits, which are occasionally almost completely dried up in summer.
The macrogonidia grow during their period of swarming from ’016 to
almost -033 mm. long; they are longish, of equal diameter on both
sides, and very obtuse, almost truncated, having a colourless place at the
ciliated extremity, presenting the form of a notch. In regard to other
points, the contents are dark green, finely granular, with a large vesicle
at the posterior extremity, a roundish lighter space in front of this, and
no red point. They multiply by simple or double halving in several
successive generations. Sometimes a further continuation of the division
of the full-grown macrogonidia occurs, forming sixteen or thirty-
two macrogonidia from '005 to '008 mm. long, of ovate shape and
lighter colour, tending towards brownish yellow. The resting oells^ are
globular, about -025 mm. in diameter, at first green, subsequently light
Yellowish brown, finally flesh-red; they have a tough, colourless, and
transparent membrane. Another species, Chi. Ungens, occurs in enormous
quantity in the puddles of the sandstone quarries at Lorettoberg,
near Freiburg, iu the month of March, in mild seasons sometimes even
in January and February. The swarming cells are smaller than in tho
preceding, '008 to '016 mm. long, ovate, lighter green, likewise destitute
of a red spot, and the membrane is more distinct in the old age. Increase
by double, rarely by simple halving, in the former case with de.
CHSsating sections.
“ Several species of this genus, previously included in the animal
kingdom, bnt nearly allied to Glceococcus and Chlamydococcus. present
themselves in the beginning of spring, in snob abundance that they
produce a striking green colouration of the w a te r; a few weeks later
they vanish, leaving no trace, and are not noticed again throughout the
whole year.”—Braun Rejuvenescence, p. 215.
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