PROCEEDINGS OF THE SOCIETY. 1111 



highest power eye-piece it gave almost, if not quite, as perfect an 

 image as those produced with lower eye-pieces. Since the date of their 

 last meeting he had been afforded the opportunity of examining very 

 carefully a set of the new lenses made by Zeiss, together with a new and 

 complete set of eye-pieces, and whilst he was perfectly convinced of the 

 immense gain which objectives of that construction would be to the 

 microscopist, he was also perfectly sure that serious errors would be 

 introduced unless they were made by the best makers. It would be 

 interesting to know that Mr. Mayall had also made a critical 

 examination of these lenses quite independently and had written down 

 the results, and that when these were afterwards compared with the 

 observations he had himself recorded, the two sets of results were found 

 to be almost exactly coincident. It was also a matter for great satis- 

 faction that Mr. Powell had added to the value of his objective still 

 further by increasing the power of his eye-pieces with such excellent 

 results. Except in one single instance, he had never seen the test- 

 objects shown better. 



Mr. Cheshire thought Mr. Powell was greatly to be congratulated 

 upon the success which he had attained, as the definition of the 

 objects exhibited by him under such a high power was magnificent. 

 It was, however, extremely difficult to compare the one with the other 

 at a distance, and he suggested that a committee might be appointed 

 to make comparisons under favourable conditions. 



Mr. Crisp said that if Fellows wanted to see the two objectives on the 

 same evening, they would be able to do so at the Conversazione on the 

 24th instant, but he was afraid the suggestion of Mr. Cheshire could not 

 be acted upon. Something of the kind had been done on a former 

 occasion, and it was found to produce more harm than good. 



Mr. Watson exhibited a new form of histological Microscope, 

 the principal feature of novelty in which was two raised edges 

 upon the stage to carry the slide, which was thus prevented from 

 scratching the surface of the brasswork, and in consequence of the 

 reduced size of the points of contact could be moved about with 

 much less than the usual amount of friction (supra, p. 1046). 



The President said this little improvement was so simple and 

 effective, that it would no doubt commend itself to all who saw it. 



Mr. C. Beck explained the additions which had been made to the 

 portable National Microscope, one of which he exhibited. 



Mr. S. 0. Ridley read a paper " On the Classification and Spicu- 

 lation of the Monaxonid Sponges of the ' Challenger ' Expedition," 

 illustrating his description of the various typical forms by drawings 

 on the black-board. 



Mr. A. Dendy also read a paper " On the Anatomy and Histology 

 of the Monaxonid Sponges of the ' Challenger ' Expedition," the subject 

 being illustrated by drawings and specimens. 



The President said the details concerning this group of sponges, 



