CONTENTS. 



TBANSACTIONS OF THE SOCIETY. 



I-AGI. 



I. — The Rotatorian Genus Diasckiza : A Monographic Study, with Descrip- 

 tion of a New Species. By F. R. Dixon-Nuttall, F.R.M.S., ami Rev. 

 R. Freeman, M.A. (Plates I. to IV.) 1,129 



II. — An Arrangement for Obtaining Monochromatic Light with the Mixed 



Jet. By Edmund J. Spitta, F.R.A.S., &c. (Fig. 1) 15 



III. — The President's Address: Some Ideas on Life. By Henry Woodward, 



LL.D. F.R.S. (Figs. 34-36) 142 



IV. — Report on the Recent Foraminifera of the Malay Archipelago collected 

 by Mr. A. Durrand, F.R.M.S.— Part XIV. By Fortescue William 

 Millett, F.R.M.S. (Plate V.) 253 



V. — A New Method of Using the Electric Arc in Photomicrography. By 



E. B. Stringer, B.A. F.R.M.S 276 



VI.— The Helmholtz Theory of the Microscope. By J. W. Gordon. (Plate VI.) 



(Figs. 76-116) 381 



VII. — On the Theory of Optical Images, with Special Reference to the Micro- 

 scope. By Lord Rayleigh. (Figs. 117-120) 447 



VIII. — On the Theory of Optical Images, with Special Reference to the Micro- 

 scope. (Supplementary Paper.) By Lord Rayleigh 474 



IX. — On the Rendering Visible of Ultra-Microscopic Particles and of Ultra- 

 Microscopic Bacterid. By H. Siedentopf, Ph.D ^~-> 



X. — A Micrometric Correction for Minute Objects. By Edward M. Nelson. 



(Figs. 139-142) .. .. 579 



XI.— On the "Lag" in Microscopic Vision — (continued). By Edward M. 



Nelson 58) '- 



XII.— Report on the Recent Foraininit'era of the Malay Archipelago collected 

 by Mr. A. Durrand, F.R.M.S.— Part XV. By Fortescue William 

 Millett. F.R.M.S. (Plate VII.) 685 



