340 PROCEEDINGS OF THE 



on February 14th (annual meeting), President's address ; on 

 March 14th, " Mounting in Glycerin with Wax Seals, with special 

 reference to Entomostraca," by Mr. B. S. Curwen. The President 

 announced that two old members of the Club had died since the 

 last meeting. Mr. Nelson had written to say that Mr. F. Hughes, 

 of Reigate, had died, and the other deceased member was Mr. 

 C, F. Rousselet. The President read a short biographical note by 

 Mr. Sheppard. Mr. Rousselet was very well known to most of 

 the members of the Club. He was born in 1854 and belonged to a 

 Huguenot family. He came to London in 1873 and joined the 

 Club in 1883. Mr. Bryce also said that he had known Mr. 

 Rousselet for many years. Before 1886 our knowledge of the 

 Rotifera was very limited. A small band of workers then devoted 

 themselves to the study of the group. Mr. Bryce worked at the 

 Bdelloid Rotifera and Rousselet looked after the rest. Rousselet 

 was the authority on the Rotifera for the whole world ; he had 

 the valuable assistance of Mr. Dixon-Nuttall, and their joint papers 

 have contributed much to the value of Q.M.C. Journal. Person- 

 ally, said Mr. Bryce, Mr. Rousselet was always agreeable and 

 pleasant, and always ready to give information. The Club 

 had sustained a great loss. A vote of condolence was passed in the 

 usual way. 



The President exhibited an ivy shoot from Florence bearing a 

 curious cup-shaped leaf. Dr. Rendle said that it was one of the 

 commonest malformations of leaves and was of interest in 

 suggesting how the pitchers of the pitcher plants may have arisen. 

 A short paper by Mr. Nelson on " Polarisation : Rings in Quartz 

 and N.A." was read by the Hon. Secretary. Mr. Nelson said that 

 the rings shown by a thin piece of quartz were given ofi at such a 

 wide angle that perhaps only one could be grasped by a wide- 

 angled objective. If the quartz was thicker the rings were closer 

 together, and it had been suggested that they might be used for 

 measuring the N.A. of objectives. This, however, was not 

 possible, as the rings were not at equal intervals of N.A. apart. 

 A table was given compiled from the measurements of more than 

 60 objectives, showing the number of rings visible with various 

 numerical apertures, and showing that equal increments of N.A. 

 require an increasing difference in the number of rings. Several 

 semi-apochromats, apparently constructed upon similar formulae, 

 were found to show more rings than they ought to from 



