CONTENTS. 
PART I. 
I. An Experimental Determination of the Velocity of Sound. By E. J. Stone, 
F.R.S., Astronomer Royal at the Cape of Good Hope page 1 
II. Maynetic Survey of the East of France in 1869. By the Rev. Stephen J. Perry. 
Communicated by the President 7 
III. On the Structure and Affinities of Guynia annulata, Dune., with Remarks upon the 
Persistence of Palaeozoic Types of Madreporaria. By P. Martin Duncan, M.B. 
Lond., F.R.S., Professor of Geology in King's College, London ..... 29 
IV. On the Fossil Mammals of Australia .- — Part V. Genus Nototherium. By Professor 
Owen, F.R.S. &c 41 
V. Corrections and Additions to the Memoir on the Theory of Reciprocal Surfaces 
(Philosophical Transactions, vol. clix. 1869). By Professor Cayley, F R.S. 83 
VI. Corrections to the Computed Lengths of Waves of Light published in the Philosophical 
Transactions of the year 1868. By George Biddell Airy, C.B., Astronomer 
Royal .89 
VII. On the Normal Paraffins. By C. Sciiorlemmer, F.R.S. Ill 
VIII. The Myology of the Cheiroptera. By Alexander Macalister, A.B., M.B. Dub., 
Professor of Zoology in the University of Dublin. Communicated by Dr. Sharpey, 
Sec. R.S 125 
IX. On the Fossil Mammals of Australia.— Part VI. Genus Phascolomys, Geofer. 
By Professor Owen, F.R.S. &c. 173 
X. On the Organization of the Fossil Plants of the Coal-measures.— Part II. Lycopo- 
diacece, Lepidodendra, and Sigillarice. By MV. C. Williamson, F.R.S., Professor 
of Natural History in Owens College, Manchester . . . . . . . . 197 
