PREFACE. 



LAST YEAR I laid before the Linnaean Society a Paper on 

 Pollen, with drawings of the various kinds. But it having 

 been brought to my notice that several German botanists 

 had written on the subject of late years, and also that HASSALL 

 had published an important paper on it, I withdrew mine 

 from before the Society. 



Since then I have altered it considerably ; having added 

 new matter, and omitted from the plates what had been 

 figured previously by HASSALL and ROMANOFF, except where 

 I differed from them. 



I also take notice of the drawings by Mr. WORTHINGTON 

 SMITH, which were published by him after my paper had been 

 laid before the Society ; and have added to the list all that 

 have been figured and noticed by former botanists on the 

 subject ; so that it may be viewed immediately in detail. 



I trust that, thus altered, this paper may prove a not 

 unimportant addition to our knowledge of the subject. 



