ZOOLOGY AND BOTANY, MICROSCOPY. KTC. 359 



The get-up of tlie volume is most excellent, and the price extremely 

 moderate. 



Quekett Microscopical Club. — The 480th Ordinary Meeting was 

 held on March 26, 1912, the President, Professor A. Dendy, D.Sc, 

 F.R.S., in the chair. Notes by Mr. E. M. Nelson, F.R.M.S., on "An 

 Aplanatic Spot-lens," " An Improved Chromatic Condenser," and " The 

 Rousselet Compressor," were read by the hon. secretary. ]\Ir. Henry 

 Sidebottom contributed an important paper on "The Lagenae of the 

 South-West Pacific." This appears in the current (April) issue of the 

 Club's Journal, and is illustrated with eight plates. Mr. C. F. Rousselet, 

 F.R.M.S., read " Some Notes on Rotifers." One new species, Brachionus 

 spatiosus, from Devil's Lake, North Dakota, U.S.A., was described. 

 Mr. D. Bryce described three new species of CalUdina. There were 

 C. nana, 0. concinna, and G. decora. Mr. A. E. Conrady, F.R.A.S., 

 made some remarks on the resolving power obtainable with dark-ground 

 illumination. No higher resolving power can be obtained, with such 

 illumination, than will be given with an objective having a N.A. of 

 0*47. Photomicrographs of Navicida Smithii sent by Mr. A. A. C. 

 Eliot Merlin, F.R.M.S., and by Dr. T. W. Butcher were exhibited. 



The 481st Ordinary Meeting was held on April 23, li)12. Mr. A. W. 

 Stokes exhibited and ' described several methods of employing electric 

 lighting for Microscope illumination. Mr. John Stevens, F.R.IM.S., 

 sent a note on the rotifer Notommata gigantea, Glascott. This is a true 

 parasite and inhabits the ova of water-snails. Dr. Duncan J. Reid 

 communicated some very useful notes on " Illumination in Critical 

 Work with the Microscope." Mr. C. D: Soar, F.R.M.S., exhibited 

 coloured drawings of the fifty British species of the Hydrachnid genus 

 Arrhenurus. 



B. Technique.* 

 (1) Collecting' Objects, including- Culture Processes. 



" Westminster " Shaking Apparatus. — This new shaker is ex- 

 pressly designed to give quiet and smooth running (fig. 7o). It was 

 exhibited at the May Meeting. A carrier or tube-holder, supported on 

 an oscillating rocker, is attached by a rigid bar to the outside member 

 of an excentric carried on a countershaft. The countershaft is driven 

 by a small electric motor. By using an excentric instead of a crank or 

 pin for driving the carrier a very quiet and smooth (practically noise- 

 less) movement is obtained. The excentric has a much larger bearing- 

 surface than a crank or pin, thus reducing the amount of wear very 

 greatly. The apparatus has been proved to be highly efficient by rigid 

 tests with various micro-organisms. The shaker (for which registration 

 has been applied for) has been designed by F. R. Chopping, Assistant 



* This subdivision contains (1) Collecting Objects, including Culture Pro- 

 cesses ; (2) Preparing Objects ; (3) Cutting, including Embedding and Microtomes ; 

 (4) Staining and Injecting ; (5) Mounting, including slides, preservation fluids, etc. ; 

 (6) Miscellaneous. 



