PREFACE. 



This Catalogue contains a Kst of the specimens of British 

 Diatomaceae in the Collection of the British Museum. It 

 is arranged according to the Rev. WiUiam Smith's ' Synopsis 

 of the British Diatomace£B.' 



The specimens were all received from the Author of 

 that work ; they form two series. The first are mounted on 

 glass slides for microscopic examination, and arranged in a 

 cabinet, as the tj-pes of his species. The second seriei^ 

 consist of masses of the species dried on paper or talc, 

 in httle paper pockets mounted on sheets of foolscap paper. 

 Each slide and pocket is marked -u-ith his initials, thereby 

 showing that they have been examined by him, and 

 represent the species described and figured in his work. 



JOHN EDWARD GRAY. 

 Nov. 1, 1859. 



