fi
Tlie above Zygnema, which Mr. Woods has so accurately
described, is also the variety of Z . quininum ((7. spiralis),
referred to by me in the 10th vol. of the “ Annals,” p. 35. I
have now, hoAvever, had numerous opportunities of examining
it in all stages of its developement, and have no doubt
about the propriety of separating it from that species from
Avhich it is distinguished hy its finer filaments, and shorter
cells, as Avell as by the manner in Avhich the sporangia are
formed; characters which arc constant.
29. Zygneiaia alternatum Hass.
Plate X X X I I I . Fig. 3.
Char. Filaments considerably finer than those o f Z. Woodsii.
Cells usually two and a h a lf times as long as hroad.
Sporangia oval, not producing any infation o f the receiving
cell.
Hab. Cheshunt: A. H. H.
I have seen this but once; it may possibly be but a variety
of the preceding species, although I can scarcely suppose that
it Is so.
30. Zygnema abbreviatum Hass.
P late X X X IV . Fig. 4.
Char. Filaments about equal to those o f Zygnema commune
in size. Cells once, or once and a h a lf as long as broad.
Sporangia oval, small, not producing any inflation o f the
cells in which they are lodged.
Hab. Cheshunt: A. H. H.
This also I have only once met with, I t appears distinct.
hoAvever,
31. Zygnema angulaee Hass.
Plate X X X IV . Figs, 1, 2, 3.
Char. Filaments at fir s t straight, hut at the period ofreproduction
becoming angulated, the angles being situated at
the junction o f the cells and produced by the tubes o f communication.
Cells usually three times as long as hroad.
Sporangia oval, producing considerable inflation o f the receiving
cell.
Zygnema angulatum Hassall, in Annals of Nat. Hist,
vol. X. p. 41.
Hab. High Beech, Fssex; and Cheshunt; A. H. H.
Mayfield, between Sharp’s Bridge and PiltdoAvn Common
; Barcombe and Framfield : ilfr, Jenner.
The angular disposition of the filaments at the period of
reproduction Is not peculiar to this species, the filaments
of most other non-conjugating Zygnemata being also angular
at th a t period. A variety of this species has occurred to
me, having cells only once and a half, or twice as long as
broad.
32. Zygnema malleolum Hass.
Plate X X X IV . Fig. 5.
Char. Filaments o f nearly the same diameter as those o f
Zygnema parvum. Cells usually about six times as long
as broad. Sporangia producing considerable inflation o f
the cells.
Hab. Cheshunt: A. H. H.
This would appear to be a distinct species, differing from
the following in the much greater length of the cells. The
empty cell taken in connection Avith the fruit-bearing cell
resembles somewhat in outline a hammer.
33. Zygnema a f f in e Hass.
P la te X X X IV . Fig. 6.
Char. Filaments o f nearly the same diameter as those o f
Zygnema parvum. Cells usually tioice or twice and a h a lf
as long as broad. Sporangia oval, lodged in cells, ivhich
are considerably inflated.
Hab. Che sh u n t: A. H. H.