150 W. H. HARRIS ON MARINE MICROSCOPIC VEGETABLE ORGANISMS. 



leave a delicate membranous or cartilaginous residue, practically 

 the remains of the mantle, but if a porcellaneous shell is similarly 

 treated it will be entirely soluble. It is quite possible that the 

 structure and chemical composition of shells may exercise a very 

 important influence upon the vegetable organisms, not only as 

 regards their development, but also the organic i-emains they 

 invade. 



I am not aware whether any work based on the following 

 lines has been done in regard to molluscan shells and, spicules. I 

 find in the Eeport on the Foraminifera dredged by H.M.S. 

 Challenger during the years 1873-76 by my late friend Mr. 

 H, B. Brady, that an attempt has been made to analyse certain 

 species of that order. The work " with two or three exceptions " 

 was done by Dr. C. R. A. Wright, F.R.S., of London, and Mr. 

 J. T. Dunn, M.Sc, of Newcastle-on-Tyne, and I feel sure no 

 apology will be necessary for its reproduction. 



Analysis of Orbitolites Complanata, var. Laciniata. 



Silica 



Carbonate of Lime 



Carbonate of Magnesia 



Alumina, with Phosphates of Lime 



and Magnesia 

 Alumina and Ferric Oxide 



IV. 



0-11 

 87-91 

 10-50 



98-52 



Operculina 

 Complanata. 



Silica 



Ferric Oxide 



Alumina, with Phosphates of Lime and 



Magnesia 



Carbonate of Magnesia 



Carbonate of Lime, with a little organic matter 



