terminate by the discovery of a specimen in Avhich perfect
sporangia were formed. The filaments, when dried on paper,
exhibit less gloss than the other species of the genus, and the
endochrome contracts but little. When the sporangia are
formed, but little difference can be detected between its filaments
and those of the following species. Where the species
does occur, it is ordinarily very abundant, destroying most
other Confervoe Avith Avhich it is in contact, by its more vigorous
groAvth. The highly developed mucous sheath, Avhich
is so characteristic of the species, frequently presents waived
and irregular margins.
3. T yndaridea lutescens Hass.
Plate X X X V I I I . Fig. 4.
Char. Filaments o f nearly the same diameter as those o f the
preceding species. Cells at fir s t scarcely so long as broad,
and f i l e d loith endochrome; subsequently they become longer
than hroad; and then the endochrome presents a partial
division, each division being somewhat stellif irm. Sporangia
circular.
T. cruciata Harv. In Manual, p. 141.
Hab. Cheshunt and its vicinity : A . H. H.
This is the species which until lately I have regarded as
the Conjugata cruciata of Vaucher, to Avhich in all, save
size, it bears considerable resemblance. I t appears to be the
commonest species of the genus ; but I am not able to refer
it to any of Vaucber’s species. Tyndaridea abbreviata. A n nals
of Nat. Hist., vol. X . p. 43, I am now inclined to think
is but this species with cells shorter than ordinary.
4. Tyndaridea bicornis Hass.
P late X X X V I I I . Fig. 5.
Char. Filaments more slender than those o f the preceding
species. Fndochrome divided into two masses, which are
united by a narrow band in the centre, each mass presenting
two points or horns on its distant extremity. Sporangia
circular, contained within the cells. Cells usually rather
more than twice as long as broad.
Tyndaridea bicornis. Annals of Nat. Hist. vol. x. p. 43,
Hab. Cheshunt and other places : A. H. H.
This species is hy no means uncommon, and is certainly
distinct. A species described in the 10th vol. of the Annals
of Nat. Hist, under the name of T. interposita, ought, I think,
to be regarded as a variety of the species. Fig. 8. plate
x x x v iii. may perhaps represent a species distinct from T.
bicornis. I have more than once met with it ju s t as represented
in the figure.
5. T, INSIGNIS Hass.
P late X X X V I I I . Figs. 6, 7.
Char. Filaments rather smaller than those o f T. bicornis.
Cells twice as long as hroad, and frequently curiously
distorted, that side o f them which either has or is about
to unite itself with another, becoming remarkably protuberant.
Sporangia circular, and partly lodged in the transverse
tubes.
Hab. High Beech, Wanstead, and other places : A . H. H.
Busthall Common; in a pool by the road-side between
Cross in Hand and Heathfield; pond near Five Ashes,
Mayfield; on Waterdown F o r e s t; Greatham and
Storrington Commons ; Mr. Jenner.
This species, which sometimes presents an appearance so
remarkable, was first sent me by Mr. Jenner, I t is by no
means uncommon, and I think certainly distinct from all
others with which I am acquainted.
6. T yn d a r id ea stagnalis Hass.
Plate X X X V I I I . Fig. 9.
Char. Filaments more slender than those o f T. insignis. Cells
about two and a h a lf times as long as broad. Sporangia
M 2