474 PE0CEEDING8 OF THE SOCIETY. 



Lacinularia to which he had drawn attention, there was any gelatinous 

 surrounding to the stem. 



The President said that the spherical portion at the top of the stem 

 was gelatinous, but the stem itself was not so ; at the upper end it was 

 white and clear, then lower down it got more horny, and became more 

 and more yellow as it continued towards the base. 



Mr. Hardy thought that the idea of making a model such as the Pre- 

 sident exhibited that evening was an extremely good one, and that if that 

 plan was more adopted they would be able to get a better idea of the facts 

 of the case than any drawing could give them. He suggested that if a 

 photograph of that model was taken under a good oblique light, it would 

 give any one a far better notion of the structure than any other mode of 

 representation. 



Mr. T. F. Smith said he had brought for exhibition the Abbe diffrac- 

 tion-plate, shown by means of stops of various apertures, to clear up a 

 point of difference between Mr. Nelson and Prof. Lowne during the dis- 

 cussion which took place at the previous meeting. Having drawn a series 

 of diagrams upon the board to represent the bands of lines on the plate, 

 parallel and crossed at right angles and obliquely, he proceeded to point 

 out that the effect of reducing the size of the aperture in the stop was 

 simply to alter the resolving power ; that where the lines were resolved 

 they were shown correctly, and where not resolved they were blotted out 

 altogether. In further illustration of his meaning, Mr. Smith exhibited 

 a number of photomicrographs of the various bands taken under the 

 conditions to which he had alluded. 



Mr, Crisp said that Mr. Smith had not explained the point he 

 desired to make as the result of his observations. 



Mr. Smith said his conclusion was that it was not possible to falsify 

 the appearance of the structure of an object with central light, and 

 that if it was resolved at all it was under those conditions resolved 

 correctly. 



Mr, Crisp inquired if Mr. Smith remembered where the contrary had 

 been stated ? 



Mr. Smith could not give the reference asked for, but thought 

 something to that effect had been stated at the Quekett Club, 



Mr. Crisp was glad to hear that it did not originate with this 

 Society ; he had feared it was some heresy emanating from them which 

 Mr, Smith was endeavouring to combat. 



Messrs, C. D. Sherborn and F. Chapman's " Additional note on the 

 Foraminifera of the London Clay " was read, describing thirty-four 

 varieties of Foraminifera from the London Clay exposed in the 

 drainage works some time since carried out in Piccadilly. 



Dr. A. C. Stokes' paper on "New Peritrichous Infusoria from the 

 Fresh Waters of the tJnited States " was read. 



The President said they had heard with great regret of the death 

 of Dr. Warren de la Hue, one who was so well known to all as a 



