I ,
i r
cells somewhat tap e r ere becoming rounded off, and the
upper margins are notably retuse a t the middle.
Siz e . Not given.
H ab.
Ireland.
Cosmarium m e lanosporum. Archer in Journ. L u ll. Mior. Club iv.
(1880-5), p. 34.
This little smooth Gosmarium, with its round, very darkly-
tinted zygospore, has not been more minutely described. I t
is said to conjugate frequently, and always freely, so th a t
when met with a large gathering may th u s sometimes be
made.
S iz e . Not stated.
H ab.
Ireland.
Cosmarium o ym a top leu rum . Nordst. Lesm. Spetz. (1S72), p. 28,
t. 6 ,/ . 4.
Large, one-third longer 'than broad, deeply constricted
with a narrow linear sinus, broad outwards, semi-cells trap e zoid,
narrow'ed upwards from a sub-reniform base, sides
nearly straight, slig’h tly undulated, dorsal margin rounded-
truncate, lower angles rounded ; end view oval, with tra n s verse
granulate folds about each p o le ; side view elliptically-
orbicular. Membrane thick, punctate.
S iz e . L e n g th 85-92 p ; d iam . 64 p (N .) ; l e n g th 82-86 p ;
d iam . 60-70 p (N .) .
Wille Nova Sembla (1879), p. 36. Nord. & W ittr.
Desm. Ital. (1876), p. 30. Nord. Desm. Arct. (1875), p. 18.
Archer Droc. Dubl. Micr. Club, 'S^ol. iv., p. 1, pp. 28, 31.
H ab. I n pools.
Deeside ; Spitzbergen, Nova Zembla, Italy.
Plate L X V I ., fig. 3. a, Hving frond ; J, empty frond ; c, end view;
d, side view; x 400. After Nordstedt.
Cosmaiium d isoxetum. Bennett in Journ. Boy. Micr. Soc. (1887),
p. 17, fig. 23.
Frond small. Seini-cells nearly semi-elliptical, or slightly
reniform, rough with pearly grannies. Isthmus very conspicuous,
separating the two frustules widely from each
other, quite colourless. Cell-memhrane punctate, and with
five distinct protuberances in each semi-cell.
S iz e . Length 3 7 | p ; diam. 1 7 | p (B.).
H a b . In hog pools.
Cornwall.
Plate L X V I ., fig. 2. a, Hving frond ; b, empty frond ; X 400. After
Bennett.
Cosmaiium sphæiicum. Bennett in Journ. Boy. Micr. Soc. (1887),
p. 17, fig. 22.
Frond moderately large. Semi-oells very nearly sphærical,
covered with very prominent projections, which give them a
very deeply crenulated edge ; sinus ra th e r deep. Endochrome
very dark green.
S ize. Length 45 p-, diam. 45 p (B.).
H a b . In hog pools.
Cornwall.
Plate L X V ., fig. 5. a, living frond ; b, empty frond ; X 400. After
Bennett.
X a n t h id iu m o o u c in n u m . Archer in Journ. Lubl. Micr. Club, TV.
(1880-5), p . 32.
Very minute (about the size of Cosmarium iinctvm), semicells
elliptioo-liexagonal, the apices bearing at each side, and at
the upper very obtuse angles, a minute but very appreciable
mucro, each front surface of each semi-cell /ow in g a distinct
median papilla ; end view compressed, showing at middle on
each side the very distinct, now prominent papilla.
Size. About 10-15 p diam.
H ab.
Ireland.
S tau ia stium tuigescens, de Not. Lesm. Ita l. (1867), p. 51, t. IV.,
fg . 43.
Medium size, resembling N. muricatum. /gm e n ts in end
view triangular, witli very obtuse angles, broadly concave at the
sides, in front view rounded-reniform, witli a narrow isthmus.
Cell membrane covered with numerous prominent papillæ.
Size. Length 40 p ; diam. 30 p (IS.).
Archer in Jonrn. Dubl. Micr. Club, iv. (1880-5), p. 17.
H a b . In ponds.
Ireland, Italy.
Plate L X V I ., fig. 4. a, living frond ; b,, empty frond ; e, end view ;
X 400.
M
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