LONDON. Royal Microscopical Society, December 20, 1911.—Mr. H. G. Plimmer, F.R.S., president, in the chair.— F. Shillington Scales: The photomicrography of the electrical reactions of the heart. The lecturer described the principle and construction of the Einthoven string galvanometer, with especial reference to the optical arrangements and the methods of photographing the movements of the wire, resulting from the differences in potential set up by the heart-beat. Photomicrographs of the movements of the hearts of various animals under the influence of drugs were shown.—Rev. Hilderic Friend: British Tubificidae. The author first gave a brief historical sketch, alluding to the work of Lankester, Beddard, and Benham, and the various Continental and other authorities who have in past years written on the family. After showing the difficulties attending definition, and the value of the setae for the purposes of classification, the author proceeded to arrange the British species in two classes:- (1) those genera which are destitute of capilliform setae; and (2) those which possess them. These two groups are again subdivided, and no fewer than thirty species, besides some subspecies and varieties, are placed on record, of which ten are described for the first time, and sixteen have been added by the author during the year. Specially interesting is the discovery of a new genus, named Rhyaco-drilus, containing two species, of which one (R. bichaetus, Friend) is new to science. These two species are as yet known only in Derbyshire. Hyodrilus is now definitely recorded as British, with no fewer than five species.