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seemingly close to Cosmarium striolatum (Niig.) ; also Xanthidium 
Smithii (Arch.), never before seen by him living, which latter is 
quite distinct from the so-called sixteen-horned variety of X. 
octocome. 
Amongst the Desmids which turned up from Glengariff were Dr. 
Barker’s Penium spirostriolatum aud the two Docidia shown by him 
at the Club Meeting in October, 1868. These occurred in consider- 
able numbers. But Mr. Archer referred to one now — the narrow, 
straight-sided, tapering form — to say, in allusion to his remarks at the 
meeting of 15th Oct., 186S (p. 195), that having seen absolutely fresh 
specimens he would still feel uncertain as to the arrangement of the 
endochrome justifying its assuming a place in the genus Pleuro- 
taenium (Niig.) ; the endochrome seemed to form a longitudinal 
mass in occasional contact with the walls, but not parietal bands. — 
Mr. Archer likewise showed the zygospores of the 16-spined so- 
called variety of Xanthidium octocome, which, like many of the 
more or less nearly allied forms, is orbicular, and beset with not 
very numerous but long acute subulate spines — in fact, they are 
fewer and longer than in any of the zygospores most resembling it. 
— He also showed Micrasterias Crux-Melitensis and M. fimbriata 
both in one gathering side by side, from near Tiunehely, Co. 
Wicklow. This is the first time the former had been found in the 
east of Ireland ; they are both certainly rare in this country, and 
neither had turned up in the lately made gatherings from Killarney 
and Glengariff. 
Mr. Archer further exhibited the conjugated state of a Penium, 
possibly new, distinguished by the fact that two zygospores resulted 
from the conjugation of each pair of parent cells. These zygospores 
were quadrate (cubical in form), thick-walled, large, and densely 
green. The Penium itself he was unable to identify with any he 
could find described, but was greatly inclined to think it might be 
perhaps identical with Penium rufescens (Cleve) ; but if not truly 
that form, it would seem to be new. It is medium-sized, stout, 
straight-sided, broadly-rounded at ends. It would, however, be 
difficult to obtain authentic specimens of Cleve’s form, nor indeed 
is its conjugated state described by him. But the formation of 
double or twin zygospores is remarkable ; this takes place in no 
other Penium yet observed, and has a parallel in that respect only 
in Closterium lineatum, C. Ehrenbergii, and in Spirotcenia con- 
densata. The almost cubical zygospores are likewise peculiar. As 
in other cases of double or twin zygospores, they are each, of course, 
formed from the union of one half the contents of one of the con- 
jugating cells with the opposite half of the contents of the other 
conjugating-cell. The empty, quite smooth, and hyaline cell-walls 
of the parent-cells become posed, and remain attached for some 
time, in a somewhat cruciform manner, each of the opposite halves 
of the conjugating cells now, however, mutually falling more into a 
line with one another than with the corresponding half of the 
original parent-cell — that is to say, calling for the moment the 
opposite ends of each parent-cell the north and south poles, the two 
VOL. IX. — NEW SER. E E 
