IX. On the existence of an element of Strength in Beams subjected to Transverse 
Strain, arising from the Latei'al Action of the fibres or particles on each other, 
and named by the author the ‘ Resistance of Flexure' By William Henry 
Barlow, Esq., F.R.S 225 
X. On the Development of Striated Muscular Fibre in Mammalia. By William 
S. Savory, Tutor and Demonstrator of Anatomy of St. Bartholomew' s Hospital 
Medical College. Presented by James Paget, F.R.S. 243 
XI. Researches on Organo-metallic Bodies. — Second Memoir. Zincethyl. By E. 
Frankland, Ph.D., F.R.S., Professor of Chemistry in Owens College, Man- 
chester 259 
XII. On the Anatomy Naiitiius umbilicatiis, compared with that o/’Nautilus Pom- 
pilius. By John Denis Macdonald, R.N., Assistant-Surgeon of H.M.S.V. 
‘ Toreh^ commanded by Lieut. William Chimmo, R.N., tender to H.M.S. ‘Herald^ 
Captain H. M. Denham, R.N., F.R.S., commanding the Expedition to the South 
Seas. Communicated by Sir WixiAXM K.C.B. Sjc. .... 277 
XIII. Remarks on the Anatomy of Macgillivrayia pelagica and Cheletropis Huxleyi 
(Forbes); suggesting the establishment of a new Order of Gasteropoda. By 
John D. Macdonald, R.N., Assistant-Surgeon H.M.S. ‘ Herald' Communi- 
cated by Sir W. Burnett, K.C.B. 8fc 289 
XIV. Further Observations on the Anatomy of Macgillivrayia, Cheletropis, and allied 
genera of pelagic Gasteropoda. By John Denis Macdonald, R.N., Assistant- 
Surgeon H.M.S.V. ‘ Torch.' Communicated by Sir William Burnett, 
K.C.B. 8^c. ... 295 
XV. On a Class of Dijf erential Equations, including those which occur in Dynamical 
Problems . — Part II. By W. F. Donkin, M.A., F.R.S., F.R.A.S., Savilian Pro- 
fessor of Astronomy in the University of Oxford 299 
XVI. On the Megatherium (Megatherium Americanum, Cuvier and Blumenbach). 
Part II. — Vertebrae of the Trunk. By Professor Owen, F.R.S. ^c. . . 359 
XVII. On Rubian and its Products of Decomposition. By Edward Schunck, 
F.R.S 389 
Index , 421 
Appendix. 
Presents 
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