296 PROCEEDINGS OF SOCIETIES. 
these were taken from the same locality as before. It was, he 
thought, interesting to find this remarkable freshwater form again 
in spring, it having been first met with in autumn of last year. 
Mr. Archer ventured to think that the exhibition of these three 
seemingly remarkable forms of freshwater rhizopods, side by side, 
would not be thought without interest; and, in bringing them 
forward, he ventured to enter into some detail in endeavouring to 
point out their peculiarities, as they seemed to him; and this he 
was the better enabled to do by simultaneously drawing attention 
to some of the commoner forms which happily presented them- 
selves—if his remarks might have been thought prolix, at least 
the objects themselves had the claim of novelty. 
Dr. A. Dickson showed preparations from the stomatic region 
of the epidermis in Taxus and Sciadapitys. In Taxus the epidermis 
cells around and between the stomata appear as if flatly tubercu- 
lated on their free surface. This apparent tuberculation, how- 
ever, is due to bulging of the cell-wall from with. There is 
thus, as it were, an elegant repoussée pattern on the surface of 
the epidermis. In Sciadapitys Dr. Dickson found this “ repoussée” 
bulging to be much exaggerated, so that, instead of exhibiting a 
comparatively flat tuberculatum, the surface was expanded into 
hollow spine-like papille. 
16th May, 1867. 
Mr. Archer showed a variety of Desmidiex conjugated. These 
zygospores were some of them only rarely seen, some never 
before. 
Amongst them was the zygospore of Mcrasterias rotata. This 
is large and orbicular, and is beset with rather large and long, 
but not very numerous, subulate spines, thus unlike the zygo- 
spore of Micrasterias denticulata (see ‘ British Desmidiex,’ plate 
vu, fig. 1 f, 7) —the more ornate form having the less ornate zygo- 
spore. Numerous examples always presented the same charac- 
teristics, and as these slender, tapering, pointed spines were 
proportionately quite as long, if not, indeed, a little longer than 
the more elaborate branched spines of JZ. denticulata, it could 
hardly be assumed that the branches had not yet begun to deve- 
lope themselves. It is thus interesting to observe the individual- 
ity seen in the parent forms of these two distinct, but no doubt 
closely related species, still further expressed and maintained in 
the zygospores. The zygospore of this species had not yet, so 
far as Mr. Archer was aware, been recorded. 
Desmidium Swartzii was also conjugated. This seems, although 
a very common, oftentimes abundant, species, to show the con- 
jugated condition but rarely. The present specimens were quite 
like that so graphically figured in ‘ British Desmidiee’ (pl. iv, 
fig. f). But Mr. Archer’s object in drawing particular attention 
