vi PREFACE 
series by themselves, and finally come the simple 
Cyanophycce. 
The account of the Rhodophycew is based on the 
scattered papers of Schmitz (p. 37), who by utilising 
his own researches and the splendid investigations of 
Thuret afid Bornet has almost wholly altered the 
classification of this sub-class. A mere outline of his 
results has been published with the effect of destroy- 
ing the earlier classification and of incompletely 
establishing his own. The full justification of his 
system will, however, be published soon, having been 
left by him almost finished at his lamented early 
death. I have thought it better to give here from 
the fragments of his work accessible to me, and from 
other sources, an account of the sub-class under his 
system, rather than revert to the old classification. 
I have to thank the Council of the Linnean 
Society, the editors of the Annals of Botany and 
Journal of Botany, and Messrs. Dulau and Co., 
publishers of the Phycological Memoirs, for their 
kindly granted permission to reproduce copies of my 
own and other figures. I am also indebted to 
M. Bornet, Prof. Reinke, Graf zu Solms-Laubach, 
Dr. John Murray, Mr. Edward Trewendt of Breslau, 
Dr. Hauptfleisch, Dr. Kuckuck, Mr. Richards, 
