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PROCEEDINGS . 



March 24th, 1871. — Chairman, Dr. Lionel S. Beale, 



F.R.S., President. 



A list of donations to the club was read, and a vote of thanks passed to the 

 respective donors. 



Mr. Hopkinson, F.G.S., read a paper on a specimen of Diplograpsus pristis. 



A vote of thanks was given to Mr. Hopkinson for his paper. 



It was announced that the club was honoured by the presence of Dr. Harkness, 

 of California, as a visitor. 



Mr. Curties announced donations of specimens of bird parasites, presented 

 through him by the Eev. J. Bramhall ; of some photographs of sections of in- 

 sects from Dr. Halifax, of Brighton, and of a series of photographs of illusory 

 appearances from Mr. Hennah, of Brighton, accompanied by an explanatory 

 letter having especial reference to the views of Dr. Pigott, in relation to the 

 headings on the podura scale. 



A vote of thanks was passed to Mr. Curties, and to the gentlemen who had 

 made the donations above referred to. 



Mr. Mclntyre said that some 14 months since, when he had read before the 

 Eoyal Microscopical Society a paper on the structure of the scales of Thysanurae, 

 Dr. Pigott's paper was read before his, and created some sensation. It did not 

 coincide with his (Mr. Mclntyre's) views, but he remained silent after hearing 

 it, because there was evidence that Dr. Pigott had seen something on the scales 

 that had escaped the notice of previous observers, although he considered his 

 interpretation of that appearance to be quite erroneous. In using high powers 

 great care should be exercised in regard to illusory appearances which were due 

 to illumination and correction of objectives, and in drawing a final conclusion 

 the work which had been performed required to be constantly checked. In re- 

 gard to diatoms, he thought all more or less presented appearances of beaded 

 hemispherical elevations ; perhaps there may be real beads like the crystals 

 seen on silica. But the term beads, as applied to the appearances observed on 

 the podura scale, had never satisfied him. He had long been aware that when 

 looking on those scales with certain kinds of illumination, beaded effects were 

 obtained, but he had always held them to be illusory. In reference to the test 

 scale, Lepidocyrtus curvicollis, the interpretation he had put on Dr. Pigott's 

 paper was that he (Dr. Pigott) was the first to find out the minute, transverse 

 striation of the scale, evidence of the existence of which has been given in the 

 photographs of the scale, taken in America. The photographs by Mr. Hennah 



