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Transactions of the Society. 
tenuissimus, Staurastrmn O’Mearii, oligocantlmm, furcatum, Griffithsi- 
anum, pygmaemn, lanceolatum, striolatum, capitulum, aversum, 
Ophiura, cerastes, and sexangulare. 
Micrasterias furcata Ag. occurs in several of the gatherings from 
Capel Curig ; both the typical form and one with longer arms. 
Euastrum verrucosum Ehrb. The typical form occurs, as well as 
Joshua’s var. simplex, 
Euastrum Jenneri Arch. Capel Curig. 
Cosmarium isthmium \A^est. I veiy much doubt whether this 
can be maintained as a distinct species. It seems to me to agree 
with C. orhiculatum Ealfs in size as in other important points. The 
width of the isthmus is probably merely an indication of an early 
stage in the process of division. 
Staurastrum hrasiliense Lund. This rare and beautiful desmid 
occurs in several of Mr. West’s slides. 
Staurastrum Ophiura Lund. I can quite corroborate Mr. West’s 
statement that all the specimens of this very rare and beautiful 
desmid observed from his gatherings are 8- or 9-ray ed, the former 
being much the most common. It is somewhat singular that, although 
Dr. Cooke describes it as “ 7 (rarely 6 or 8) rayed,” he figures it as 
8-rayed. The papillae in the centre I find to be numerous, scattered, 
and simple, not few, quadrifid, and arranged in a coronet ; in fact, 
the Welsh specimens agree with both Cooke’s and Wolle’s figures 
better than with their descriptions. 
Staurastrum cerastes Lund. In several slides from Capel Curig. 
Staurastrum vestitum Ealfs. Capel Curig. 
