xxii Proceedings. {March 8th, i8g8. 



Ordinary Meeting, February 22nd, J898. ' 

 James Cosmo Melvill, M.A., F.L.S., President, in the Chair. 



The thanks of the members were voted to the donors of the 

 books upon the table. 



The President announced that Professor Michael Foster 

 would deliver the Wilde Lecture before the Society on March 29th. 



The President exhibited an interesting series of distortions 

 and hyperstrophical deformities of Planorbis spirorbis L., found 

 by Mr. Arthur Stubbs at Black Rock, Tenby. These distortions 

 included (i) evolute whorls, (2) various forms of carination, 

 (3) sinistral turbinate spirals, and (4} dextral turbinate spirals. 

 The causes for such malformations are at present practically 

 unknown, but may be traced to the obstructions to the active but 

 tender-shelled mollusc caused by duckweed and confervae. 



A discussion on the subject of inversion of vision was after- 

 wards participated in by several members. 



Ordinary Meeting, March 8th, 1898. 

 James Cosmo Melvill, M.A., F.L.S., President, in the Chair. 



The thanks of the members were voted to the donors of the 

 books upon the table. 



The President announced that the title of the Wilde 

 Lecture, to be delivered by Professor Michael Foster, would be 

 " On the Physical Basis of Psychical Events." 



Mr. T. Thorp exhibited some celluloid films taken from 

 Rowland's gratings of 14,438 lines to the inch. By making use 

 of the refractive properties of prisms, the first and second orders 

 of spectra are obtained by direct vision. The dispersion is such 

 as to easily separate the two D lines, and is practically normal. 



