West & West. — Observations on the Conjngatae. 49 
chrome. Bientot les deux globules se rapprochent vers 
la partie renflee de la cellule et finissent par se reunir en 
constituant ainsi la zygospore.’ 
The vegetative cells of the genus Debarya are like those of 
Mougeotia. The conj ugating-tubes of D . glyptosperma are 
long, some of them very long, and when they do not happen 
to meet with a fellow they often become club-shaped. As 
the cell-contents pass into the conjugating-tube the chro- 
matophore takes the form of a loop, and a peculiar change 
comes over the empty cells as the zygospore is being formed ; 
they become very clear and refractive, and a series of striations 
parallel to the transverse septa become visible. After this has 
taken place the cells have the appearance of solidity, this ap- 
pearance being possibly due to annular thickenings deposited 
inside the cell-wall on the receding of the protoplasm during 
conjugation ; in any case this character stands out distinctly 
in both old preserved specimens and in living ones. The 
large size of the zygospore is also a noticeable feature. 
In D. laevis the conj ugating-tubes are shorter and thicker 
and the spores are proportionately smaller. We give a figure 
of a specimen of this plant which has conjugated in a re- 
markable manner (Fig. 58). It has two to four pyrenoids in 
each chromatophore. 
Mougeotiopsis , a genus recently described by Palla 1 , seems 
to us to differ in no way from Debarya , except in the absence 
of pyrenoids. This is certainly in itself an insufficient generic 
character, and might probably be caused by the conditions 
under which the plants were growing. Lagerheim 2 states 
that Mougeotia laevis belongs to Mougeotiopsis ; it is, how- 
ever, a true species of Debarya , and as stated above certainly 
contains pyrenoids. The zygospores of both Debarya laevis 
and Mougeotiopsis calospora are scrobiculate, which seems to 
further indicate the identity of these two genera. 
1 E. Palla, Ueber eine neue, pyrenoidlose Art und Gattung der Conjugaten, 
Ber. der Deutsch. Botan. Gesellsch., Jahrg. xii (1894), Heft 8, pp. 228-236, 
T. XVIII. 
2 G. Lagerheim, Ueber das Phycoporphyrin, Vidensk.-Selsk. Skrift., I. mathem.- 
natur. Kl., Kristiania, 1895, No. 5, p. 16 (Sep.). 
E 
