PROCEEDINGS OF SOCIETIES. 63 
Mr. Archer further exhibited some rare minute alge, amongst 
which were Cdogoniwm Itzigsohnii (de Bary) in fruit (vide de 
Bary, ‘ Ueber die Algengattungen Oedogonium und Bulbochete,’ 
p. 56, t. iii, f 29-32). This minute species Mr. Archer had 
picked up several times, and often showing its peculiarly-lobed 
oogonium, but he had never found the male fructification ; he 
believed the plant must turn out to be a dicecious species; he had 
sometimes noticed a minute notch-like depression on the upper 
outer margin of the oogonium, probably indicating the “ micro- 
pyle.” He drew attention to the character, not adverted to by 
de Bary, that the apical or terminal joint of the filament possessed 
ashort acute spine or mucro. This, in old plants, frequently is 
not to be seen, as the terminal joint, or, indeed, considerable por- 
tions of the filaments, often become detached, and chiefly in a 
young condition only are the plants found entire. 
Mr. Archer likewise showed specimens of Leptocystinema 
Kinahani (ejus). This well-marked plant he had but once found 
since he ventured first to describe it (‘ Proceedings of the Dublin 
University Zool. and Bot. Association,’ vol. i, pp. 94, 105 ; also 
Nat. Hist. Review,’ O.S., vol. v, p. 234.) The present specimens 
were gathered by Captain Hutton on a late visit to the County 
Donegal, and- kindly given to him by that gentleman. Mr. 
Archer had never seen this plant conjugated, but, beyond doubt, 
it must so reproduce itself, and it would be interesting to note 
any minor peculiarity which it might present during that process. 
There was also shown by Mr. Archer the form called Plewro- 
coccus superbus by Cienkowski (see ‘ Botanische Zeitung,’ No. 3, 
Jan., 1865, p. 21). He likewise exhibited Ophiocytiwm apiculatum 
(Nag.) and Polyedrium tetraedricum (Nag.). 
June, 15th 1865. 
Dr. Moore exhibited a Sirosiphon= Hassallia compacta (Hass.). 
Dr. Moore also showed specimens of Chroolepus Arnottii, ob- 
tained by Admiral Jones in Scotland. Dr. Moore had himself 
taken this plant in Ireland, but he regarded it as very rare. 
Mr. Archer mentioned that Admiral Jones had kindly given 
him a specimen of the plant shown by Dr. Moore. Mr. Archer 
had never met it near Dublin, and could only refer it to Chroo- 
lepus, but was afterwards informed by Admiral Jones that it was 
OC. Arnottii. In looking over the specimens Mr. Archer thought 
he could perceive the torulose filaments formed by this plant to 
be accompanied by slender cylindrical filaments, attached to the 
former, and apparently of the same nature as those appertaining 
to Chroolepus ebeneum. Now, in this latter Mr. Archer was quite 
disposed to regard these accompanying filaments as part of the 
