Contents. 



May 18, 1891. page 



On Parasitic Mollusca. By A. H. Cooke 215 



Exhibition of models of double supernumerary appendages in Insects : 

 also of a mechanical method of demonstrating the system upon 

 which the Symmetry of such appendages is usually arranged. By 



W. Bateson 219 



On the nature of the excretory processes in Marine Polyzoa. By S. F. 



Harmer 219 



June 1, 1891. 



On the part of the parallactic class of inequalities in the moon's motion, 

 which is a function of the ratio of the mean motions of the sun 



and moon. By Ernest W. Brown . 220 



On Pascal's Hexagram. By H. W. Richmond 221 



On a Linkage for describing Lemniscates and other Inverses of Conic 



Sections. By R. S. Cole 222 



On some experiments on liquid electrodes in vacuum tubes. By C. Chree 222 

 Note on a problem in the Linear Conduction of Heat. By G. H. Bryan 246 



October 26, 1891. 



On the Absorption of Energy by the Secondary of a Transformer. 



By Professor J. J. Thomson 249 



On an experiment of Sir Humphry Davy's. By G. F. C. Searle . . 250 



Some notes on Clark's Cells. By R. T. Glazebrook and S. Skinner . 250 

 Illustrations of a Method of Measuring Ionic Velocities. By W. C. D. 



Whetham 250 



On Gold-Tin Alloys. By A. P. Laurie 250 



November 9, 1891. 



Note on a Peripatus from Natal. By A. Sedgwick .... 250 



On "Variations in the Colour of Cocoons (Saturnia carpini and Eriogaster 



lanestris), with reference to recent theories of Protective Coloration. 



By W. Bateson 251 



Exhibition of Phylloxera vastatrix. By A. E. Shipley .... 252 

 The Digestive Processes of Ammoccetes. By Miss R. Alcock . . . 252 

 On the Reaction of certain Cell-Granules with Methylene-Blue. By 



W. B. Hardy 256 



