r
a protoplasmic gonosphere, coloured by chlorophyll, containing numerous
starch grannies ; it presents at one point of the periphery very often a
clear spot. The gonosphere is loosely enclosed by the several (3-6) concentric
gelatinous (as it were swollen or expanded) membranes. Such
oogonia lie either several together, forming a moniliform chain, or they
present themselves in the middle of a series of antheridia, or between
unaltered vegetative joints, upon which, further on, may abut antheridia.
Cylindrocapsa is thus monoicous. At both poles of the oogonium the
coats are produced into a short cylindrical process ; adjoining processes
are mutually apposed. The size of the oogonia varies ; it may reach
042 mm., the gonosphere *024 mm.
“ The antheridia are discoid or sphseroidal little cells, like the oogonia
possessing a multi-laminated coat, they may form a long series or little
groups of pairs ; they are often enveloped in twos or fours by numerous
laminæ. The contenta are clear reddish yellow. The male cells (like
the vegetative) are formed by binary division of the mother joint, with
the distinction that they cease to grow, remain smaller, and gradually
assume the yellowish red colour. Each antheridium developes by division
of its contents two spermatozoids. At maturity they are ejected
with a jerk ; when free, they lie for a while motionless enclosed in their
gelatinous envelope. Presently they assume a tremulous motion, at last
bursting the vesicle and swimming about. They are protoplasmic fusiform
bodies of about '015 mm. in length, contents sparing, yellowish
red ; at the anterior hyaline point are borne two flagella, below which
are two minute pulsating vacuoles.
“ Shortly after their exit they are to be found in the neighbourhood
of the oogonia. The whole cavity of the oogonium becomes pushed out
laterally, dissolving and leaving an opening at the apex of the expansion.
The spermatozoids seem now to be no way aimless ju their movements,
their whole object being seemingly to effect a penetration ; with great
energy they drive against the wall, and retreat, and so persist for hours,
until at last the movement ceases, and they shrink into formless little
masses. The actual confluence of the spermatozoid with the gonosphere
was not observed, but the conclusion drawn by the author seems to be
legitimate.
“ The next change consists in the appearance of a thick gelatinous
stratum directly on the surface of the gonosphere, which soon hardens
into a doubly contoured membrane. After some days the chlorophyll with
the starch grannies gradually disappear, becoming replaced by the
reddish-yellow oily substance. In this way we obtain from the gonosphere
an oospore surrounded by the mncous layers of the oogonium. The
author could never see any further development ; they lasted the whole
autumn and winter without the slightest alteration.
“ In some instances the gonospheres on having become enclosed by
the gelatinous envelope began to germinate ; they divided iuto two
Begnients, each then becoming clothed by its own gelatinous envelope,
and soon divisions followed just as in the ordinary vegetative joints.
The author supposes that these still green gonospheres could not have
been fertilized, and that only the latter pass over into a state of rest."
— Quart. Journ. Micr. Sci., 1877, p. 181.
Genus 17. HYDRURUS. Ag. (1824.)
Thallus adnate, gelatinous, more or less firm, tubular, elongated
(2-4-12 inches long), sometimes variously divided, sticky,
surface naked or densely covered with delicate fibres, which at
times are fasciculate. Cells in the beginning globose, or subglobose,
afterwards elongated, or elliptic, sometimes conoid, one
or other pole colourless, arranged more or loss regularly in longitudinal
families; tegument thick, at length diffiuent, cells
dividing in one direction, chiefly at the apex or periphery of the
thallus. Propagation by means of agile gonidia.
Hydruxus p en ic e lla tu s . Ag. Syst. p. 24.
Thallus ra ther cartilaginous, olivaceous, of variable thickness,
simple and naked below, divided above, and villous with dense
fibrils. Internal cells elliptical or somewhat lanceolate ; tegument
very thin, scarce visible ; contents homogenous.
Rabh. Alg. iii. 50.
Hydrurus fcetidus, Vauch. Kirch. Alg. Schl. p. 106.
var. e. D u c lu z e lii. Rabh. Alg. iii. 50.
Thallus from an inch to a foot long, oftentimes sparingly
branched, plumose with very dense fibrils.
S iz e . Cells -OOQ-OOOb mm. (Rabh.).
Hydrurus Ducluzelii, Ag. Consp. p. 27. Hass. Alg. t. 77, f.
3. Rabh. Exs. 176, 873, 1193.
Batracliospermwm myosurus, Ducluz. Conf. Montp. p. 76.
Palmella myosurus, Lyngb. Hydr. t. 68, E .
Cluzella myosurus, Bory. Diet. iv. 234.
In alpine rivulets, on stones, rooks, &c.
“ Root scutate, blackish, hard. Fronds clustered, solid, very gelatinous,
2-6 inches long or more, 2-4 lines in diameter, freely waving in
the water, attenuated towards the apex, branched ; branches scattered,
alternate, elongate, slender, beset with other more slender, short ramuli.
Gelatinous mass pellucid, viscid, colourless under the microscope, without
apparent margin, unless as the grannies imbedded within its substance
indicate such ; these are globose, green, formed on the stem and primary
branches, most densely set in the ramuli, especially towards the margin.
Colour of the recent frond brownish-olive, or dark brown, in drying
green ; of the granules both recent and dry green.”—Lyngbye.
Odour in a recent state very offensive.
One or other of the many forms of this species has been called
Palmodactylon subramosum, Nag,, bnt we have not, as yet, seen any
true British representative of that genus.
Plate X . fig. 4. a, natural size ; b, portion magnified 400 diam.
Genus 18. NEPHROOYTIUM. Nag. (1849.)
Cells oblong kidney-shaped, with a dorsal chlorophyllose
vesicle, 2-4-8-16 associated in free swimming families surrounded
by an ample oval or kidney-shaped tegument. P ro pagation
unknown.
Only two European species, both of which have been fonnd in the
British Isles. Both are usually found together, and it is possible that
hereafter they may be referred back to one species, as Nageli pro