567 



and lamp upon a Japanese tray, which could then be passed round 

 a table without disturbing the adjustment of the light. 



Mr. Piovanelli's paper, describing two parasitic rotifers found 

 on the common fresh-water crab of Italy, was read by Mr. Bryce. 

 The rotifers were exhibited under microscopes in the room, and 

 living specimens of the species of crab from which they had been 

 taken were passed round for inspection. 



Mr. Bryce also read a description of two new species of 

 Philodinae. 



The thanks of the meeting were cordially voted to Mr. 

 Piovanelli and to Mr. Bryce for their communications. 



Mr. Cheshire read a paper " On Abbe's Test of Aplanatlsm, 

 and a simple Apertometer derived therefrom," * in the course of 

 which he described various methods of examining the back focal 

 plane of an objective, and demonstrated the method now pro- 

 posed by exhibiting the arrangement on the table. 



Mr. Hilton enquired if the difigram which it was proposed to 

 issue with the next number of the Journal would be large 

 enough to be of use for the purpose described. 



Mr. Cheshire said it would be large enough to answer for the 

 whole series of dry objectives in common use. 



The thanks of the meeting were unanimously voted to Mr. 

 Cheshire for his paper. 



Mr. E. T. Lewis read a short note describing the contents of 

 three bottles of entomological specimens w^iich had been sent to 

 the Club from Queensland by their fellow member Mr. C. J. Pound. 



Mr. Scourfield gave a resume of a paper he had written in 

 continuation of the series which was to form a synopsis of the 

 British Fresh- water Entomostraca. 



Mr. Scourfield also read a paper by Mr. Ashe on some instan- 

 taneous photographs of the curious appearance of ebulhtion 

 which seemed to take place in the cavities of topaz, a diagram in 

 illustration being drawn upon the board, and the photographs 

 also exhibited. 



The thanks of the meeting were voted to Mr. Scourfield and 

 Mr. Ashe, and the ordinary meetings were then adjourned to 

 October 16th. 



* This paper Las been unavoidably held over, but will be publi^hed in 

 the next number of the Journal. 



Journ. Quekett MicroscoiAcal Club, Ser. 2, Vol. VIII., No. 53, November 19C3. 



