PROCEEDINGS OF SOCIETIES. 



Dublin Miceoscopical Club. 

 20th January, 1870. 



De. John Baekee exhibited the dotted structure of Pleuro- 

 sigma formosum under his dark-ground illumination, as also some 

 fine rotatoria, which were shown in a very beautiful manner and 

 with great comfort to the vision on a completely dark field, the 

 effect, viewed binocularly, being very pleasing. Some were 

 shown very satisfactorily under higher powers ; more detailed 

 results of his experiments in this direction Dr. Barker would 

 prepare for a future occasion. 



Dr. Moore showed exceedingly pretty stellate hairs from a 

 Japanese fern, a species of Niphobolus, well adapted as a polari- 

 scope object. 



Kev. E. O'Meara exhibited a slide containing several interesting 

 diatomaceous forms, for the possession of which he was indebted 

 to the kindness of Gr. M. Browne, Esq., of Liverpool. The 

 material was obtained from the careful washing of oyster shells 

 picked up in Dublin Bay. Among the species of rare occurrence 

 found in this slide were Nitzschia specfabilis, Coscinodisciis omplia- 

 lanthus, and Cos. concinmis ; the last-named was but a fragment, 

 but large enough to leave no room for doubt as to its identity. 

 Special attention was invited to two species of great rarity and 

 interest : Actinocyclus triradiatus, Eoper, and Navicula hicuneata, 

 Grunow, and Cleve. The former species, though found in England, 

 Mr. O'Meara had never before obtained from an Irish locality. 

 The latter, so far as he could ascertain, has not been hitherto 

 recorded as having been discovered in the United Kingdom. The 

 only localities in which it had hitherto been found are the 

 Adriatic Sea at Porto Piccolo, near Castel Muschio (Grunow), 

 and Gullmaren in Sweden or Norway (Cleve). Grunow's de- 

 scription is as follows: — Navicula hicuneata, nov. spec. — " On the 

 secondary side linear, slightly constricted in the middle, ends 

 obtusely cuneate, median line direct, central nodule slightly 

 oblong, transverse strise, fine, longitudinal stria3 obsolete, two not 

 very conspicuous submargiual sulci, length 0'0048", breadth 

 00010" ;" colour of the dried frustule violet-brown. Grunow, 

 " Ueber neue oder ungeniigend gekannte Algen." ' Verhandl. 



