[ ‘ri ] 
YIIT. On the Development of the SJcull in Lepidosteus osseus. By William Kitchen 
Parker, F.R.S. .*. page 443 
IX. On the Vibrations of a Vortex Ring, and the Action upon each other of Two 
Vortices in a Perfect Fluid. By J. J. Thomson, B.A., Fellow of Trinity 
College, Cambridge. Communicated by Lord Rayleigh, F.R.S. . . . 493 
X. The Bakerian Lecture. — Chemical Theory of Gunpowder. By H. Debus, 
PhD., F.R.S. . 523 
XI. On the Refraction of Plane Polarized Light at the Surface of a Uniaxal Crystal. 
By B. T. Glazebrook, M.A., Fellow and Assistant Lecturer of Trinity 
College, Demonstrator in the Cavendish Laboratory, Cambridge. Communi¬ 
cated by Lord Bayleigii, ALA., F.R.S. . 595 
XII. On the Results of Recent Explorations of Erect Trees containing Animal 
Remains in the Coal-formation of Nova Scotia. By J. W. Dawson, LL.D. 
F.R.S., C.M.G ... 621 
XIII. Experiments to determine the Value of the British Association Unit of 
Resistance in Absolute Measure. By Lord Bayleigii, F.R.S., Professor 
of Experimental Physics in the University of Cambridge . 661 
XIY. On the Comparative Structure of the Brain in Rodents. By W. Beyan 
Lewis, L.R.C.P. (. Lond .), Senior Assistant Medical Officer , West Riding 
Asylum, Wahefield. Communicated by Dr. Ferrier, F.R.S. ... .699 
Index to Part II. .747 
PABT III. 
XY. On a Class of Invariants. By John C. Malet, M.A., Professor of Mathe¬ 
matics, Queen’s College, Corh. Communicated by Professor Cayley, LL.D., 
F.R.S. .751 
XYI. Description of portions of a Tush of a Proboscidian Mammal (Noteleplias 
australis, Owen). By Professor Owen, C.B., F.R.S., &c .777 
XYIL Memoir on the Theta-Functions, particularly those of two Variables. By A. II. 
Forsyth, B.A., Fellow of Trinity College, Cambridge. Communicated by 
Professor A. Cayley, LL.D., F.R.S. .783 
XVIII. On Seismic Experiments. By J. Milne, F.G.S., and T. Gray, B.Sc., 
F.R.S.E. Communicated by A. C. Ramsay, LL.D., Director-General of the 
Geological Survey, and of the Museum of Economic Geology .863 
