232 PROCEEDINGS OF SOCIETIES. 



and he believed that there were many found on the Continent which 

 were unknown here. Mr. Ward had recently found one which gave 

 some very pretty effects under the microscope. 



Mr. Slack called attention to the portion of Dr. Anthony's paper in 

 which the opinion was expressed that the ribs were on the under side 

 of the scale, and the cross-hatching was upon the ujjper surface, and 

 asked if Mr. Mclntire's observations had led him to the same conclusion. 



Mr. Mclutire thought that the results of Mr. Beck's experiments 

 quite tended in that direction, and seemed to show that on the upper 

 side there were the cross-markings, and on the side next the insect 

 there were the ribs, 



Mr. Slack said it was very desirable to find out, if jjossible, what 

 sort of lepisma the scales were taken from. In the ordinary lepisma, 

 where the beading was to be seen, it was brought out very plainly by 

 transmitted light. The peculiar markings drawn in illustration of 

 the paper he had tried to find, but had not been able to do so ; he 

 had, however, only one slide of lepisma scales, and many of these had 

 ribs which were very wide apart. He would write to Dr. Anthony 

 about it, and ask him if he knew what species the scale he described 

 was taken from. 



Mr. Mclntire mentioned that he had seen foui" or five kinds of 

 lepisma scales, and they were very different from each other. 



The Chairman thought it was rather an interesting discovery, and 

 it looked almost as if they would have to begin their work upon scales 

 all over again. The ordinary method of obtaining the scales was to 

 lay a glass cover on the back of the insect in order that some of the 

 scales might adhere to it, in which case, of course, the upper side was 

 that which was looked at ; they would now have to mount them the 

 opposite way as well. There were, no doubt, different kinds of 

 lepismte. He had seen one kind in the tropics which was about 

 J inch long, and he wondered if the scales of these would be pro- 

 portionately large. 



Mr. Mclntire did not think it was necessarily the case that large 

 scales were obtained from large insects ; they were sometimes got 

 from very small ones. The different kinds of scales were very dif- 

 ferent from each other ; he could call to mind three, and knew that 

 there was also one from the Cajie. 



The thanks of the meeting were then unanimously voted to Dr. 

 Anthony for his communication. 



Mr. Wenham said that at the previous meeting he had promised 

 to give them a demonstration of his method of measuring the angular 

 apertures of objectives. He then i^roceeded to do so, and illustrated 

 his remarks by an instrument j^laced ujion the table, and by diagrams 

 drawn upon the black-board. (See pp. 233, 234.) 



Mr. Ingpen said that, upon reading Mr. Wenham's letter in the last 

 number of the 'Monthly Microscojjical Journal,' it occurred to him that 

 the same method might be employed with advantage to get rid of false 

 light by cutting off all extraneous rays. His favourite Eoss |-inch 

 objective, of 100^ ajierture, which was extremely good with oblique 

 light, always showed a blaze in the centre of the field of view when 

 used with direct light. He had a cap made to slide upon it with an 



