globules of the other species of the same family ; on the contrary,
the green matter Avhlch it incloses has appeared to
me to present nearly the same form, so that I know not how
the grain is formed, nor in what Avay the developement in this
species is brought about ; only I have remarked distinctly
three or four bright grains immersed in this green matter,
and I have seen in the month of April the cells separate
from each other and sink in the water, but I traced them no
further. Nevertheless, I have difficulty in believing tha t the
brilliant grains are not the germs.
“ ‘ Since writing this description I have seen the germination
of this Conjugata elsewhere in a manner very different
from all the others : the matter does not pass from one tube
to another neighbouring tube, but each cell itself furnishes
a single young plant, the interior tube which it was found to
enclose becoming a young Conjugata which was entirely contained
in the old tube, as it itself contains the plants which
are afterwards to become developed ; it Issues by the extremity
Avhen it occupies the last cell, and by the sides when
it is found in one of the central cells.’
“ W ith respect to the observations of Vaucher in reference
to the germination of the young Conferva while still within
the parent cell, I Avould observe th a t I have never witnessed
this singular developement, and can confidently assert that
this is not the legitimate or normal mode of developement of
the species of the genus Mougeotia, which is by zoospores, developed
external to the cells, as in other Confervoe.”
1. M o u g e o t ia m a jo r Hass.
Plate X L . Fig. 1.
Char. Filaments o f considerable size. Cells usually fiv e times
as long as hroad.
Mougeotia major Hassall, in Annals of Nat. Hist. vol. x.
p. 44.
Hab. Cheshunt : A. H. H.
F ith e r this species and the following are subject to very
considerable variation, or else several species, really distinct,
liavc been Improperly referred to tlicm. A t one time, entertaining
the latter opinion, I was induced to add three other
species to the genus ; but not finding, on subsequent examination,
that these species were well established, I shall omit all
fig. 9.
p. 79.
mention of them in the present work.
2. M o u g e o t ia g e n u f l e x a Ag.
P late X L . Fig. 2.
Char. Filaments o f smaller diameter than those o f M. major.
Cells seven or eight times as long as broad.
Müller, Acta Petropolitana, pars 3. p. 92. pi. 1.
Conjugata angulata Vaucher, Hist, des Conf.
pi. 8. figs. 1, 2, 3, 4.
This interesting species is one of the commonest of the
Avhole tribe of freshwater Confervoe, and there Is scarce a
ditch in which it may not be found at all seasons of the year
The tubes remain connected for a very long time after conjugation,
and this explains why it is that the species should
so constantly be found united. For Vaucher’s account of its
reproduction see page 172.
14. ZY GO G O NIUM Kützing.
Char. Filaments o f equal diameter, rarely branched. Cells
seldom conjugating; transference o f endochrome rare.
Sporangia none. Fndochrome at fir s t filling the cavity
o f the cell. Zoospores scattered without order through the
colouring matter.
Derivation. From fyyos, a yoke, and ywvia, an angle.
This genus seems to me to be well established. A t first
I felt disposed, on perceiving tha t the filaments of C. ericetorum
were occasionally branched, to refer the species to the
branched Confervoe, acknowledging, at the same time, that in
many points it resembled the conjugating Algæ. Subsequently,
on finding union to have taken place between some