vi. author's preface. 



Every effort has been made that the work should present as faithful 

 a conspectus as possible of all the forms found within the prescribed 

 area; but, notwithstanding, it is greatly feared that a certain number of 

 them has escaped the Author's notice. The Author requests the 

 readers of this Volume to be good enough to inform him of any omissions 

 they may discover, so as to enable him to insert them in the French 

 Edition, which he hopes to publish shortly. 



Mr. Wynne E. Baxter, who is himself a skilful Diatomist, has been 

 good enough to translate this work, and publish it for the benefit of 

 English diatomphiles. He has performed this task with every possible 

 care, and with his usual ability. Both amateurs and the Author owe 

 a debt of gratitude to Mr. Baxter for the great sacrifice at which he 

 has published the Work. 



H. V. H. 



Botanical Gardens, Antwerp, 

 \gf/i September, 1896. 



