174 PROCEEDINGS OF THE SOCIETY. 



fine details in photography, and consequently the exposure of the 

 plate has to be considerably augmented, with corresponding risk of 

 movement of tlie image. 



I venture to remark upon two points referred to at the preceding 

 meeting : — 



1. In reply to the President, the length of the valve photographed 

 is about H\ hundredths of a millimetre — that is to say, slightly 

 smaller than the valve photographed by the late Dr. Woodward, of 

 Washington, which was about 9^ hundredths of a millimetre. The 

 average valves of A. pellucida vary, according to W. Smith, between 

 84 and 137 /x. 



2. In reply to Mr. Beck, I used the term ' beads ' in its popular 

 sense, as remarked by Mr. Crisp. On this matter I may refer to the 

 note 2, p. 7 of my Synopsis." 



Dr. Gray's note was read, warning microscopists that balsam of 

 tolii was a failure as a mounting medium on account of its tendency 

 to develope crystals {siqn-a, p. 160). 



Mr. Crisp exhibited Eobiuson's " microscopic photographic " 

 camera ; Gibbes's membrane-stretcher ; and new live-cell {supra, 

 p. 13i). 



Mr. Swift exhibited the cone condenser (which he had made in 

 January 1883) and achromatized immersion paraboloid condenser 

 referred to supra, p. 126. 



Dr. Anthony's letter as to Mr. Wright's observations on the 

 structure of the tongue of the blow-fly was read, as follows : — 



" Will you kindly make known the fact that the professedly new 

 matter with respect to the ' tongue of the blow-fly,' narrated in Mr. 

 Wright's letter, read at the November meeting, was communicated to 

 the microscopical world some ten years ago. I had the honour to 

 read a paper on this subject on May 6th, 1874, in which the soft 

 parts of the fly's tongue in connection with the chitinous rings of the 

 pseudo-tracheje were fully described and figured ; and this paper, with 

 its illustrations, will be found on reference to the June number of the 

 ' Monthly Microscopical Journal ' for 1874, p. 242. The paper was 

 undertaken for the purpose of calling attention to the existence of a 

 singularly beautiful set of soft parts — presumably suctorial — in the 

 tongue of the fly, which I believe that no one previously had observed, 

 seeing that they were not visible in that popular microscopic object 

 when mounted in the then lasual mode — viz. in Canada balsam — the 

 preparation showing only the chitinous skeleton of the tougue, and 

 that not too well. 1 will not suppose for a moment that Mr. Wright 

 has plagiarized wilfully, but rather that he has rediscovered the 

 matter he described. At the time I wrote. Topping's ' tongue of 

 the blow-fly,' duly squeezed flat, and put in that treacherous Canada 



