CONTENTS OF PART III. 



XII. A NEW PART OF PACHYTHECA. By THE EDITOR. 



XIII. CALCAREOUS PEBBLES FORMED BY ALG^E. By THE EDITOR. 

 With LIST OF DIATOMS. By E. GROVE. 



XIV. NOTES ON THE SORI OF MACROCYSTIS AND POSTELSIA. 



By A. L. SMITH and F- G. WHITTING. 



XV. A COMPARISON OF THE ARCTIC AND ANTARCTIC MARINE 

 FLORAS. By THE EDITOR and E. S. BARTON. 



PRICE ys. 6d. 



