*
Structural difference between tbe two.” The whole of the commmiioa-
tion from whence the above is quoted is worthy of attentive perusal,
at least in so far as the relations between Ulothrix and ScUsogomnni
■are concerned. It is entitled “ On the Diamorphosis of Lyngbya, &o.,”
in the “ Quart. Journ. of Microscopical Science ” for 1861, pp. 157-166.
S chizogonium m ura le . Kutz. Tab. Phyc. n ., t. 98,/. 1.
Dark green, forming a broadly expanded soft velvety
stratum, threads sometimes free, here and there two or three
united, cells 2-4 times sliorter than their diameter, pectinate,
often crowded, sometimes interrupted, cell membrane rather
thick, colourless, slightly undulated and constricted.
S i z e . C e lls - 0 1 5 - - 0 1 8 m m .
Eabh. Alg. Eur. iii., 368. Kiroh. Alg. Schl. 78.
On moist walls and naked ground.
Plate L X X I. fig. 3. Portions of threads of Schizogonium murale
X 400 diam.
F a m i ly Y I I . CHROOLBPIDEÆ. .
Aerial algæ, coloured golden yellow, orange or red-brown,
when dry often becoming greenish grey ; more or less f r a p a n t
with the odour of violets. Threads articulate, variously
branched, cell membrane thick, or somewhat thick, firm, almost
cartilaginous, collected in minute tufts, or densely interwoven
in a thin or thick tomentose stratum. Cell contents oily or
granulose, either red, orange, or yellow brown, growing paler
after death.
Propagation by zoogonidia, produced in proper cells
(sporangia) which are terminal, or by prolification formed
laterally. Zoogonidia oblong-oval, furnished at one extremity
with two vibratile cilia.—Rahh. Alg. Eur. m ., 371.
Gen. 69. CHROOLEPUS. Ag. (1824.)
Characters the same as given above for the family.
There appears to ns no occasion or justification for the substitution
of Trentepohlia for the above generic name as some authors have
’‘“ he following is an abstract of the process of reproduction, as observed
by Dr Caspary. {Flora, Sept. 28, 1858). The apical cell of
the threads has often' a globular or pulvinate
refractive nature, fiiniisbed with transverse wrinliles, and Gequeffilj
élsoUUh a protubérance at tbe top. The whole cavity of the cells is
filled with granular matter, mostly of a brownish red colour, but it
frequently happens that the inner grannies only are brownish red.
whilst the outer ones are green. The reddish brown granules seem
to be oil drops A groat number of the threads terminate with a globose
much thickened cell, which subsequently becomes the mother ooU of
the zoospores. This mother cell is rarely found in the middle of the
threads. Oooasionally, but still more rarely, the cell immediately under
the mother cell elongates itself sideways and upwards into a thread.
The mother cell ot the zoospores, when it forms the terminal cell of
the thread, bears a conical mass of gelatine, often of considerable size,
which, however, is seldom on the crown of the cell, but usually at its
side. In those mother cells in which the zoospores are about to escape
a division of the contents into small oval cells is clearly perceptible,
and at the side, or near the top, the wall is extended into a short
papilla. The contents emerge in the form of a well defined vesicle,
with the zoospores penetrating through the ruptured papilla, sometimes,
however, no vesicle is formed. A few moments after emerging
the vesicle bursts, doubtless by absorption of water, and the zoospores
swim about in every direction. The remnants of the vesicle are of a
gelatinons nature. The escape of the zoospores was observed from nine
in the morning till four in the afternoon, and seems to depend not npon
the influonoe of light, but solely upon the effect of moistening with
water. The zoospores are very small, 'OOSd-'OOSS mm. They are
filled with reddish brown granular matter, the apex alone being free
and hyaline ; there are two cilia, about three or four times as long as
the spore. The apex with the cilia is directed forwards. They rotate
perpetually whilst swimming; their motion being so rapid as to prevent
a clear view of them, except when stopped by some obstacle, or when
their motion is becoming retarded. The cell is surrounded by a clear
highly refractive border looking like gelatine, but which may be only
an optical appearance. After continuing in motion for about an hour
the zoospores beoome sluggish, sink, beoome globular, elongate themselves,
and shortly a division of the cell takes place by a transverse
septum. Some reddish brown granules usually remain behind iu the
empty mother cell, and in the remnant of the vesicle. Oftentimes
some zoospores cannot emerge from the mother cell, and then they
sometimes germinate in it. These observations were made on a variety
of Chroolopus aureus. Quart. Journ. Alicro. Science, viii. (1860), p.
159,
Chioolepus auzeu s. {Linn), Kutz. Tab. w., f. 93.
Golden red or orange. Threads eitlier collected in small
tufts, or spreading in a soft silky stratum, sometimes intricately
and densely expanded and very much branched. Cells as long,
or two to three times as long as their diameter.
S iz e . Cells •01--012 mm. diam. Zoosporangium -02 x
•03 mm.
Eng. Fl. v., p. 380. Eng. Bot. ii., t. 2528. Harv. Man.
189. Mack. Hib. 246. Rab. Alg. Eur. iii., 371.
Conferva aurea, Dillw. Conf. t. 35.
Byssus aurea, Eng. Bot. i., t. 212.- Lightf. PI. Soot. p. 1002.
Hull Br. Fl. 307. Relhan Cant. 446. Huds. Fl. Ang. 606.
Sibth. Ox. 888. Purton Midi. Fl. ii., 606. Ray. Syn. 56, No.
6. Abbot. Bedf. 276. With. Arr. iv., 144.
Ceramium aureum, Hook. Fl. Scot. ii., 86.
Amphicomum aureum, Johnst. Fl. Berw. ii., 243.
‘ I.
! i \