PROCEEDINGS OF THE SOCIETY. 
273 
sequently unable to read liis paper as they had hoped. The paper had 
been sent to the printer, but it had been returned to him without the proof 
of the plate by which it was to be illustrated, and not having therefore 
the opportunity of comparing the figures with the descriptions given in 
the text, he was unable to give a sufficiently clear explanation of the 
very minute details entered into by the author. He gave, however, 
such a resume as was possible under the circumstances. 
Prof. Stewart, who had seen some of Mr. Michael’s specimens, 
pointed out the chief features illustrated by the diagrams. 
The Chairman expressed the thanks of the Society to Mr. Michael 
for his communication, and the regret which he was sure they felt at his 
absence. 
Mr. C. H. Wright gave a description of a new British hymeno- 
lichen, and exhibited specimens lent for the occasion from the herbarium 
at Kew. His observations led him to the conclusion that the species was 
Cyconema interruptum, which he believed to be a synonym of Bliizonema 
interruptum, Sbud that in future descriptions the last-mentioned term must 
be omitted. 
Prof. Bennett regretted that he had not been able clearly to hear the 
observations of Mr. Wright, but if he rightly understood the purport of 
his remarks, it was that this form must in future be referred to the 
genus Cyconema, which was an exceedingly polymorphic family. He 
thought it was a fact of great interest to have found this form in this 
country. 
Mr. E. M. Nelson read a short note with reference to a statement 
alleged to have been made at one of the meetings of the Society, to the 
effect that it was impossible to produce images of external objects from 
the markings of P. formosum, and he said it had been contended that the 
production of such images did not prove that the openings were len- 
ticular. Images could be seen so long as they were within the resolving 
power of the lenses employed. 
Mr. Crisp said he was present at the meeting referred to by Mr. 
Nelson, but did not hear any one say that images could not be produced 
in P. formosum, because it was well known that in P. formosum they 
could. Dr. Matthews having shown them. The whole point was that 
they could not do it after they reached a certain limit, and P. angulatum 
being beyond that point, they could not see them there. 
Mr. Mayall said that P. formosum might be within the limit, but 
P. angulatum was never within it so far as he knew. He remembered 
that the question was submitted some years ago to Prof. Abbe, and he 
replied that P. formosum was, generally speaking, within the limit. 
Mr. T. F. Smith would have thought that if they had a cross shown 
by P. formosum, and they also had one produced by P. angulatum, it 
would point to their being of the same structure. 
Mr. Mayall would be glad to have the matter of fact first demonstrated 
by the production of photographs of the image of a cross produced by 
the structure of P. angulatum ; the rationale of the phenomenon might 
then be a subject for useful discussion at the Society. 
Mr. Crisp suggested a prize to be offered in connection with this 
1890. T 
