Neph x o cy tium Agaxdhianum. Nag. Einz. Alg. p. 80.
Cells pale green, almost homogenous, 4-6 times as long
as broad, spirally arranged, in families of 4-8 c ells; teg u ment
thin wliicb encloses them, length 2-3 times the breadth.
S i z e . Cells diam. •0038--0075 mm. (Eabh.).
Eabh. Alg. iii. 52. Nag. Einz. Alg. {forma minor), t. iii.
C. a-h. Kirch. Alg. Schl. p. 112.
In ditches, bogs, &c.
Plate X I. Jig. 1. a, b, families; o, end view ; d, free cells. All
magnified 400 diam.
Nephxocytium N a e g e lii. Grun. Rabh. Alg. I I I . 53.
Cells dark green, granular, twice as long as broad, irregularly
disposed, families usually composed of 16 cells ; teg u ment
thick.
S iz e . Cells diam. •011--022 mm. (Rabh.).
Neplirocytium Agardhianum, magus Nag. Einz. A lg .t. iii. C.
fig. i, k, p. Kirch. Alg. Schl. p. 113.
In similar or the same places as the foregoing, with which
it is often associated.
Rlate X I. Jig. 2. a, b, c, family groups j d, free cells.
All magnified
400 diam.
Genus 19. OOCYSTIS. Niig. (1855.)
Cells oblong, chlorophyllous, either solitary or binate, qiia-
ternate, or octonate; contained at first within an ample simple
mother cell, at length free by dissolution of the membrane.
This genus, as Mr. Archer has observed (Micr. Journ., 1877, p. 105),
comes very near NepTirocytium, the seemingly only very tangible distinction
(it is a very constant one at the least), being the reniform (not
elliptical) cells in the latter genus; but as forms merely, of more or
less frequent occurrence, those referred to both the genera are indeed
very distinct and constant.
Oocystis g ig a s. Archer, Quart. Journ. Slier. Sci., 1817, p . 105.
Mother-cell broadly elliptic, almost subglobose, la rg e ; family
usually consisting of two cells.
S iz e . Mother-cell ■06-07 X ‘OS-'Oe mm.
In pools. Ireland.
The broadly elliptical cells are very large, and are really subsphserioal.
“ The cell wall,” Mr. Archer says, “ is by comparison very thick, with
the somewhat nodular little thickening at each pole; the chlorophyll
granules, in examples in which these were not too dense, could be seen
arranged parietally in a beautifully and curiously regular reticulate
manner, the ‘ meshes or interspaces of the interior surface of the wall
being bare of them. He had only seen two young cells within theex-
panded mother-cell, four, eight, to sixteen being common in Oocystis
Naegelii. In examples about to produce young individuals, the contents
became more dense, and the reticulated arrangements lost, or rather,
perhaps, more properly speaking, the interspaces become clothed with
chlorophyll granules. At first glance this might be mistaken, under a
low power, for that small form of Eremosphmra viridu, which originates
when the individuals of the ordinary large form produce simultaneously
four, in place of two daughter cells; bnt the evident elliptic
figure and the thickened poles, as well as the different arrangement of
the chlorophyll contents, would, on closer inspection, at once distinguish
them. Mr. Archer has drawn attention to the seemingly curious very
great expansion of the wall of the mother-cell, almost looking as if m
anticipation, rather than as in consequence of the growth of a young
‘ brood ’ of two, four, eight, or sixteen daughter-oells, so much so that
it almost had the aspect of a fresh growth, rather than that of a mere
swelling up of the old membrane.”— Journ. Micr. bc%„ 18/7,
p. 105.
Oocystis se tig ex a . A r c h e r , in Quart. Jowrn. Micr. Se i.,1877, p.lOi.
We are unable to give any description of this species which,
as far as we are aware, bears only a manuscript name. Neither
are we able to give figures of either species, although we hope
to do so hereafter.
Genus 20. D IM 0R PH 0C 0C C U 8 . Br. (1849.)
Cells united in fours on very short branches, dissimilar, the
two intermediate contiguous oblique, obtuse ovate, the two
lateral, opposite and separate from each other, lu n a te ; families
free swimming, in botryoid clusters.
This genus is allied to Dictyosphcerivm, next to which it should have
been placed.
Dimoxphococ cus In n a tu s. Br.Alg. Uni.p-4A.
Green, apices of the cells hyaline.
S iz e . Cells longitudinal diam. •01--02 mm.
Eabh. Alg. iii. p. 36. Archer, Quart. Journ. Micr. Sci.,
1872, pp. 195, 197.
F loating in pools. N. Wales.
We have been unable to make a successful drawing from the
specimen we possess of this Alga, as we have not seen it living. Mr.
Archer, on reporting upon its occurrence in Ireland, criticised the only
figure extant (in Eabenhorst’s Alg. Eur.) in the following terms : “ The
upper or outermost cells do not, as they are made to seem, or as the
original description might lead one to infer, stand above the larger and
lower (inner) cells as upon a common stipes, but the former grow oil
from the latter, and remain joined thereto by a short pedicle. The inner
cels are broadly reniform, and two stand opposite to each other at the
apex of the supporting stipes, so as to present a lunate figure, and from
the lower part of the sinus made by these it is that the pedicle of each
of the pair of secondary, more or less reniform, but unequally lobed,
cells (one from each lower cell) starts, the smaller lobes of these latter
overlapping each other, and appearing, in a crowded cluster, like one
cell, only of smaller dimensions, concentrically posed above the lower