PKEFACE. Yll 



W. Daws, F. H. Day, H. M. Edelsten, F. W. Edwards, 

 J. Edwards, W. Evans, Gr. E. Frisby, H. Gruermonprez, 

 J. N. Halbert, A. H. Hamm, B. S. Harwood, W. Hewett, 

 W. Holland, W. J. Jones, F. C. R. Jourdain, S. W. 

 Kemp, C. Gr. Lamb, G. T. Lyle, B. McGowan, H. Main, 

 H. Moore, C. Morley, K. J. Morton, J. Nicholson, Gr. T. 

 Porritt, R. B. and Miss Nellie Robertson, A. 0. Rowden, 

 E. Saunders, D. Sharp, Eland Shaw, A. Sich, E. J. B. 

 Sopp, R. South, A. M. Stewart, E. A. C. Stowell, J. R. 

 le B. Tomlin, H. R. Wakefield, J. J. Walker, W. West, 

 0. Whittaker, J. W. Yerbury, and many others who 

 have kindly helped in a similar way. 



Most of the Irish localities are due to specimens in 

 the collection at Trinity College, Dublin, the list of 

 which was communicated by S. W. Kemp: hence the 

 reference -fide Kemp. 



All the plates and figures have been reproduced 

 from the author's drawings or photographs, with the 

 exception of Plate IV, fig. o, and the whole of Plate VI, 

 which are from photographs by H. Main, B.Sc. ; 

 Plate XVIII, fig. 3, from a photograph by G. T. Lyle ; 

 and Plate IV, fig. 1 from a photograph by the late H. F. 

 Hayman. 



In a work containing so much detail and involving 

 so many references it would be too optimistic to expect 

 that no error has escaped notice ; but if the corrigenda 

 have been reduced to a minimum, the result should be 

 attributed to the assiduity with which the late Secre- 

 tary of the Ray Society, Mr. J. Hopkinson, brought 

 his great experience to bear in piloting the book along 

 its passage through the press. 



W. J. LUCAS. 



KlNGSTON-ON-THAMES ; 



July, 1919. 



