LONDON Royal Microscopical Society.—The opening meeting of the session was held at King's College, Oct. 1, C. Brooke, F.R.S., president, in the chair.—The secretary read a paper by Dr. Maddox descriptive of an organism found in a pond of fresh water in the New Forest, near Lyndhurst, which it was proposed to name Pseudo-amœba violacea. The general appearance of the organism was minutely described and figured, and the results of a series of continuous observations upon a growing slide under the microscope were detailed.—A paper by Mr. F. Kitton, of Norwich, describing some new species of Diatoms, was taken as read, and the attention of the meeting was called by the president to one of great beauty named by Mr. Kitto Aulacodiscus superbus.—Mr. F. H. Wenham made some interesting observations upon the microscopical appearance of glass which had been subjected to the action of the American sand-blast process, showing that the erosion of the surface was entirely due to the percussive force of the particles of sand, and that the results of this were demonstrated by the polariscope. A number of specimens were exhibited in the room.—Mr. C. Stewart, the hon. sec., exhibited under the microscope, and minutely described, a beautiful preparation of the spermatophores of the common squid; he also explained and illustrated the general structure of the generative organs of the male cuttle-fish.