il CONTENTS. 
PART IL. (1873-1874.) 
TX.—On the Establishment of the Elementary Principles of Quater- 
nions on an Analytical Basis. By Gustav PLARR, Docteur 
es-sciences. Communicated by Professor Tarr, 
X.—WNotice of Fossil Trees recently Discovered in Craigleith Quarry, 
near Edinburgh. By Sir Rosert Curistison, Bart., 
Honorary Vice-President R.S.E. (Plate XIII), . 

PART III. (1874~-75.) 
XI—On the Embryogeny of Tropxolum peregrinum (L.) and T. 
speciosum (Endl. and Poepp.) By ALEXANDER Dickson, 
M.D. Edin. & Dublin, Regius Professor of Botany in the 
University of Glasgow. (Plates XIV—XVL), 
XII.—On the Mode of Growth and Increase amongst the Corals of 
the Paleozoic Period. By H. ALLEYNE Nicuotson, M.D., 
D.Sc., F.R.S.E., Professor of Biology in the Durham 
University College of Physical Science. (Plate X VIL), . 
XIU.—On the Elimination of a, B, y, from the conditions of integri- 
bility of S uadp, S uBdp, S wydp, By G. PLarr, Docteur 
és-sciences. Communicated by Professor Tarr, 
XIV.--On the Placentation of the Seals. By Professor Turner. 
(Plates X VIII.-XX1), 
XV.—Essay towards a General Solution of Numerical Equations of 
all Degrees having Integer Roots. By H. ¥. TAusot, F.R.S., 
XVI—A Contribution to the Germ Theory of Putrefaction and other 
Fermentative Changes, and to the Natural History of 
Torule and Bacteria. By Josepu Lister, F.R.S., Pro- 
fessor of Clinical Surgery in the University of Edinburgh. | 
(Plates XXII.-XXVL), 
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