Vlll CONTENTS OF VOL. XXXTI. FOURTH SERIES. 



Page 

 Mr. P. M. Duncan on the Madreporaria of the Infra-lias 



of South Wales 544 



Mr. H. Woodward on some points in the structure of the 



Xiphosura 545 



On the Tangent Photometer, by Dr. F. Bothe 546 



On the Conductivity of Mercury for Heat, by G. Gripon .... 547 



Index : • 548 



PLATES. 



I. Illustrative of Prof. R. Bunsen's Paper on Flame Reactions. 



II. III. Illustrative of Prof. R. Bunsen's Paper on the Phenomena ob- 

 served in the Absorption-spectrum of Didymium. 



IV. Illustrative of Mr. R. Gill's Paper on an Air-pump without Clearance 



V. Illustrative of Mr. R. Walker's Paper on Ancient Shell Mounds at 

 St. Andrews. 



VI. Illustrative of Mr. R. Templeton's Paper on the Index of Refraction 

 of the Lens. 



