IV CONTENTS. 



4 

 ARTICLE PACK 



XIII.— On a mode of Isolating the Siliceous Shells of Infusorial Animals 



found in Ichaboe Guano. By H. Deane, Esq. - - - 80 



XIV. — A New Application of Polarized Light in examining every description 



of Objects. By John King, Esq. - - - - - 81 



XV. — On the Application of Polarized Light in Microscopic Investigations. 



By M. S. Lego, Esq. - - - - - - 83 



XVI. — Observations on Xanthidium, both Fossil and Recent. By Samuel 



James Wilkinson, Esq. - - - - - - 89 



XVII. — On Chara vulgaris. By Cornelius Varley, Esq. - - - 93 



XVIII. — On the Structure and Formation of the Nails of the Fingers and Toes. 

 By G. Rainey, Esq., M.R.C.S., Demonstrator of Anatomy, St. 

 Thomas's Hospital. Communicated by John Quekett, Esq. - 105 



XIX. — Observations on the Shepherd's Purse Coralline of Ellis (Notamiu bur- 



saria, Fleming). By George Busk, Esq., F.L.S. - 110 



XX. — Addendum to the Paper on the Application of Polarized Light in Mi- 

 croscopic Investigations. By M. S. Legg, Esq. ... 122 



XXI. — Observations on the Anguinaria spatulata. By George Busk, Esq., 



F.L.S., &c. 123 



XXII. — On an Improvement in the Stage of the Microscope. By M. S. Legg, 



Esq. - 127 



XXIII. — On a New Medium for mounting Organic Substances as Permanent 



Objects for Microscopic Inspection. By Robert Warington, Esq. 131 



XXIV. — On Micrometers. By George Jackson, Esq. ... 134 



XXV. — Observations on the Anatomy of the Skin of a Species of Murama. 



By Andrew Clark, M.D. Communicated by J. E. Gray, Esq. - 141 



XXVI. — On the Value of the Microscope in the Determination of Minute 

 Structures of a Doubtful Nature, as exemplified in the identification 

 of Human Skin attached many Centuries ago to the Doors of 

 Churches. By John Quekett, Esq., Assistant Conservator of the 

 Museum of the Royal College of Surgeons of England - - 151 



XXVIL— On the Structure of the Shell and Soft Animal of Polystomella 

 crispa; with some Remarks on the Zoological Position of the Fora- 

 minifera. By W". C. Williamson, Esq., of Manchester - - 159 



ERRATA. 



Page 86, line 10 from the bottom, dele " upon the brass-mountings." 



Page 87, line 6, for ventral read neutral. 



Page 88, in the explanation of fig. 3, dele " by means of the glass." 



