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are the young spores, which undergo a marvellous variety of transforma,
tions. At first they are contiguous, but as they contract they become
free, though variable in shape, and with their chlorophyll distributed in
a thousand different ways. Finally they beoome spherical and almost
completely filled with chlorophyll interspersed with some starch granules,
and covered with a thin, smooth layer of plastic matter, but not with a
cellulose membrane.
“ Long before the foregoing process has taken place, the cell-wall
proper of the thread has undergone some peculiar chemical alterations,
all tending to^ its final dissolution to free the fully-developed spores.
Frevious to this, however, little apertures are formed in it at certain
points, varying in diameter from one 500th to one 300th of a line.
“ All the cellules of the same filament do not undergo the modiflca-
tims described. In a large number of them the phenomena are quite
different, the green rings, interspersed with colourless vacuoles,
gradually change to a reddish yellow, and the grains of starch disappear.
Soon the coloured matter thus formed becomes granular, and
IS finally broken np into innumerable rod-like oorpusoles.”
Thus the cycle is completed, and we need not pursue the abstract
further. Plate L l l . will serve to illustrate the various changes.
Sphaeroplea a n n u l in a . (JlotU) Ag. Syst. p. 76.
Green, yellowish, brick-red, or scarlet, cells 8 to 10 or 20
times as long as broad, with 20 to 30 chlorophyllose rings in
each cell; spores at length densely seriate, rarely disposed
irregularly, at first green, afterwards olive-brown, and then
red.
SizB. Threads ■036-’07 mm. diam., oospore ‘OlS-'OSG mm.
Eabh. Alg. Enr. iii., p . 318. Eabh. Alg. ex. 309, 455, 147."
Cohn, m Acad. Berl. 1855, p . 835. Ann. des. Sci. Nat. 4 ser.
(1856) V., t. 12-13. Cienkowski, Bot. Zeit. (1855), p 777
Freseniiis Bot. Zeit (1851), p. 241. Braun, Eejuvenescence
p. 164, 271, 281»
Conferva annulina, Eoth. Cat. iii,, p. 7.
In quarries, pits, or inundated fields.
Cohn has remarked that whereas most confervoid Algas vegetate bv
repeated snbdivision of the terminal cell, being at some time or other
attached by the base, the present has both extremities alike, and
neitber of them rooting, moreover the vegetation is carried on by
sub-division of the central cells, so that the terminal cells remain the
oldest.
Plate L l l . fig. 1 , Portion of filament of ^heeroplea annulina vrifh
the green cytioplasm in rings X 400. Fig. 2, cells showing the formation
of spermatozoids X 400 with escaped spermatozoids s below. Fig
3, spores having acquired a globose form being fertilized by spermal
tozoids. Fig. 5, spores in an earlier stage. Fig. 8, isolated spore with
spermatozoid attached. Fig. 6, mature spores, having acquired an
vT o n stellate outline, the primary membrane is detached
A lUU. Jiig. 7, cells showing arrangement of mature spores X 300
tig . 4, resting spore in various stages; a, mature ; b, divided iuto 2 ■ i
and further subdivided. Fig. 9, zoogonidia X 400. Fig. 10, germination
of zoogonidia X 400. All except Fig. 7 after Cohn.
F a m i ly III. CONFERVACEj®.
Threads articulate, either simple or branched, vegetation
terminal, unlimited. Articulations more or less elongated,
rarely abbreviated, now and then shorter than the diameter,
cylindrical, rarely swollen. Cell membrane sometimes manifestly
lamellose. Chlorophyllose mass granulate, containing
starch granules, effused, parietal, or sometimes contracted in the
centre of the cell.
V eg e ta tio n by th e rep e a ted division of the primordial u tric le
in one direction.
Propagation by zoogonidia.
Genus 58. IBCICROSPORA. Thur. (1851.)
Articulate thread simple. Chlorophyllose mass at first
parietal, afterwards contracted in the centre. All articulations
fertile.
Propagation by zoogonidia. Zoogonidia arising from a
simultaneous division of the cell contents, small, numerous,
ovate-elliptical, cuspidate and colourless at one end, usually
furnished with two, rarely 3 to 4, cilia, escaping by rupture of
the cell.
H lic io sp o ia fu g a c is s im a . (Ag. Syst. p 43.)
Pale green, or yellowish green, articulations before division
4 to 5 times as long as their diameter, after division about 2 to
24 times as long, not constricted at the joints.
SizB. Cells -OOSS-Ol mm. diam.
Eabh. Alg. Eur. iii., 821. .
Conferva fugacissima, Grev. Fl. Ed. 317. Gray Arr. i., 310.
Kirsch. Alg. Schl. p. 80.
In ditches.
Plate L I I I . fig. 1. Portions of threads of M. fugacissima X 300
diam.
IKEiczospoza v u lg a i i s . Rahh. Alg. Eur. III., 321.
Bright green, articulations 2 to times as long as the
diameter.
Siz e . T h re ad s-012 mm. diameter.
Conferva bombycina iiimqualis, Kutz. Tab. iii., t. 44, f. 3.
Microspora bombycina, Thuret. Eech. p. 12.
Conferva vulgaris, Kirsch. Alg. Schl. p. 79.
In ditches and pools.
Plate n i l . Jig 2. Portions of threads of M. vulgaris X 300 diam.