suppl) of pal witli the difficulties ol the 



subject, rb such a one Nature will surel) reveal some ol its 

 secrets, and tame will be forthcoming to the pioneei in these 

 realms of the " Infiniment petits" 



Others besides myself have understood the necessity for 



summary treatment of cert, tin groups of the Diatomacese. In 



r by, Greville, Roper, Brightwell, H. L Smith, and a 



few others led the way, and at the present time a new genera 



tion is following their lead. Anion- the latter I may mention 



Captain of Artillery, II. Peragallo, who, between the practical 



technology of breechloaders and melinite, has found time to 

 prepare a valuable paper on the genus Pfeurosigma % with outline 

 figures of all the species and diagrams ol the striation. Prof. 

 1'. I'. Cleve, of the University of Upsal, is far advanced on a 

 general work, to comprise the numerous and difficult Navicula. 

 Dr. Leuduger-Fortmorel is giving his special attention to the 

 curious but very perplexing Chcetoceri ; while Mons. |. Tempere 

 promises a complete Monograph of the Aulacodisci, being a cri 

 tical review and a supplement to John Rattrey's "revision'" of 

 this genus of beautiful microscopical gems. 



I am grieved to have to state that English and S 

 botanists — who some years ago occupied the head of Diatomo- 

 logy under the brilliant phalanx of such men as Greville, 

 Gregory,.W. Smith, Brightwell, Roper, Norman, Walker-Arnott, 

 C.Johnston, Ralfs, Tuffen West, Donkin, and others have at the 

 present day arrived at a minimum of working naturalists. It is 

 true that we ^till have the satisfaction of possessing among the 

 living such men as Mr. Grove, Mr hied. Kitton, and Mr. John 

 Rattrey ; but these, as well as many others, have become 

 reduced to ubiquitous collectors and mounters of I )iaton, 

 have (eased publishing their observations. Many of these 

 gentlemen excel in their specialties, and none more so than the 

 venerable Mr. Laurence Hardman. who at the advanced a. 

 82 is still able to prepare admirable type-plates ol' Diatoms con- 

 taining hundreds of forms arranged in symmetrical patterns with 

 a precision which brings astonishment and envy to the pi 



