AUTHOR'S PREFACE xi 



Holborn, W.C., for permission to photograph their 

 diatom preparations in Figs. 13 and 15 ; also of 

 C. Baker, 244 High Holborn, W.C., for the use 

 of all the preparations illustrated in chapter iii., 

 except Figs. 44 and 52 ; and likewise of Mr. 

 C. E. Burnell, of Henley, Shepton Mallet, for the 

 use of the insect dissections shown in Figs. 1 20, 

 136, and 163 ; and lastly, of Mr. R. Hancock, of 

 Handsworth, Birmingham, for the various pre- 

 parations shown in Frontispiece and Figs. 27, 28, 

 29, 38, 104, 112, 116, 118, 123, 124, 125, 127, 130, 

 144, 147, and 1 6 1. 



I am also greatly obliged to Mr. E. Kay 

 Robinson for his most helpful revision and 

 emendation of my work. 



J. J. W. 



