TRANSACTIONS OF THE ROYAL MICRO- 

 SCOPICAL SOCIETY. 



DESCRIPTION OF PLATE VII, 



Illustrating Dr. CoUingwood's paper on the Microscopic Alga 

 which causes the Discoloration of the Sea in various parts 

 of the World. 



Fig. 

 A. — Slieaf-fonn of Trichodesmiuni, from the Northern Indian Ocean (seen 

 with a lens). 



B. — Ordinary wedge-form of ditto, characteristic of the China Sea (nat. 

 size). 



c. — Ditto (seen with a lens). 



D. — The fimbriated ends magnified, showing the loose, simple, filamentous 

 structure. 



E. — A single filament (higlily magnified). 



F. — Single cells in process of disruption. 



G. — OsciUatoria, found in conjunction with Trichodesminm (nat. size, and 

 with a lens). 



H. — A normal filament of Trichodesmium Ehrenbergii (from Moutagne). 



I. — Extremity of a filament of Trichodesmium Hindsii (from Montague). 



