The Editor wishes to express his sincere thanks to the Council of 

 the Zoological Society of London, the Council of the Manchester 

 Literary and Philosophical Society, and to the editors of the " Morphol. 

 Jahrbiicher," " Quarterly Journal of Microscopical Science," " The 

 Annals and Magazine of Natural History,'' " The Annals of Botany," 

 " The Liverpool Museum Bulletin," and of the " Ber. d. Deutschen 

 Botanischen Gesellschaft," for permission to reprint the articles which 

 appear in this volume. 



