270 PROCEEDINGS OF SOCIETIES. 
varying in this regard from nearly quadrate to three or four times 
longer than broad, according to the interval of time elapsed since 
division ; the contents bright herbaceous green, forming an axile 
compressed band (never separate stellate chlorophyll bodies, as in 
Zygnema) ; the conjugation taking place by short, wide processes, 
which, along with the shortness of the cells or joints, gives the 
pair of conjugating filaments somewhat the appearance of a per- 
forated ribbon-like structure; the total cell-contents of each pair 
of conjugating jomts become massed together into an elliptic 
zygospore within the inflated transverse tube ; the longer diameter 
of the zygospore placed vertically to the length of the filaments; 
the cavity occupied thereby not shut off by any septum from the 
cavities of the parent joints. . 
That the total cell-contents, “primordial utricle” and all, 
wholly coalesced to form the zygospore, Mr. Archer had com- 
pletely satisfied himself both by there being no granular matter 
whatever left behind in the parent conjugated joints, and by no 
further contraction of any contents taking place on the applica- 
tion of re-agents. In the same way it was equally evident that 
there was no septum separating the zygospore from the cavities 
of the parent-cells, but it lay freely in the inflated transverse 
process, though frequently in contact with its walls about the 
middle. 
A seemingly fair figure of this type is given in Rabenhorst’s 
‘Kryptogamen-Flora von Sachsen,’ &e., p. 162; but the plant is 
referred by that author to Zygogonium in the Kiitzingian sense, 
and de Bary’s characters are not taken into consideration. Little 
information can be drawn from the figure referred to as regards 
the arrangement of the endochrome in the unconjugated joint, 
whether doubly stellate or forming a compressed band. If the 
former it would be a Zygnema, with the zygospore in the middle. 
It may be assumed, however, that the figure may represent the 
broad or flat view of the band of endochrome as towards the 
observer. Therefore, Rabenhorst’s figure would be still more 
likely to represent a plant congeneric with the present, seeing 
that here the whole cell-contents are represented as fused into the 
spore, which is not shut off by any septum from the cavities of 
the parent joints. 
Now, the foregoing characters of the plant now exhibited, as 
has been described, would seem at once so decisive that it should 
be referred to Mougeotia (de Bary, non Agardh), and not to 
Zygogonium in either sense, that it might almost be asked why 
there should be any question on the subject, or any allusion to 
the genus Zygogonium, de Bary, or Zygogonium, Kiuitz., as con- 
nected with it. For the definition of this well-marked genus 
(Mougeotia, de Bary, non Ag.), see de Bary’s already quoted 
work (pag. 78, t. viii, figs. 20—25), also Mr. Archer’s observa- 
tions thereon, and on the only hitherto established form therein, 
Mougeotia glyptosperma, de Bary, in the ‘ Microscopical Journal,’ 
vol. xiv, p. 65 (in the separate copies of the Club Proceedings, 
