viii PREFACE. 



the Eydrozoa of the Cambrian and Silurian rocks. Since the early portion of the volume 

 (pp. 4-14)^ was printed, I have been compelled by the researches of Professors Lapworth and 

 Nicholson, Mr. Hopkinson and others, to rearrange in part the Group GraptoUthoidea. The 

 old genus GraptoUthus has thus been entirely recast and other genera have been greatly 

 modified. The Flora of the Carboniferous Rocks, through Professor Williamson and Mr. 

 Kidston, and the Cephalopoda (Tetrahranchiata) of the Silurian Rocks, through the able 

 monograph by Professor F. Blake, M.A., have received material additions ; and the 

 investigations of Mr. J. W. Davis, of Halifax, have largely increased our knowledge of the 

 Fishes of the Carboniferous Rocks. The Supplementary Index (p. 465) fuUy attests the 

 numerous additions which have come to hand since the printing of the volume began, and 

 references are therein made to 409 genera, 305 of which are new, illustrating 11 56 species. 

 The species catalogued in this volume through the five divisions of Palajozoic time, as before 

 stated, number 6022. It is hoped that only a few may have escaped notice, and that, if such 

 omissions occur, they will be pardoned by those who have passed through the ordeal of critical 

 research extending over many years and carried on after the hours devoted to official duties ^. 



The publication of this Catalogue of the British Palaeozoic FossUs is whoUy due to the 

 liberality and consideration of the Delegates of the Oxford University Press, for which I beg to 

 tender my sincere thanks. 



R. ETHERIDGE. 



1 4 Caeltlb Square, Chelsea : 

 Aug. 1, 1888. 



' See note on Monograptus, p. 394. 



^ The remainder of the Catalogue, comprising the Mesozoic and Cainozoic genera and species, to the number of 13,000, 

 is completed in manuscript, and the history of all the known British fossils is thus brought down to the present year 

 (1888). The pressure of departmental duties does not leave me sufficient leisure to prepare this work for publication, 

 so as to render it available to those who might find it of equal value with myself in the prosecution of Pateontological 

 research. 



