x PREFACE. 



The material upon which this work is based is principally, 

 though not exclusively, contained in the extensive collections 

 of Corals which I have made from the Palaeozoic formations 

 of Britain, the Continent of Europe, and North America ; but 

 I have also had the opportunity of consulting the collections of 

 the British Museum, the Museum of Practical Geology, and 

 the Edinburgh Museum of Science and Art. The method of 

 investigation which I have adopted has been largely that of 

 microscopic sections, and the present work is, therefore, much 

 more extensively occupied with detailed descriptions of minute 

 structure than has been usual in treatises or memoirs dealing 

 with the fossil Corals. For the same reason I have been more 

 concerned to investigate the actual anatomy and systematic 

 relations of even perfectly well known types, than to describe 

 new forms or to discuss difficult and disputed points of specific 

 determination. The necessary sections, with few exceptions, 

 have been personally prepared by myself, and the illustrations 

 of microscopic structure are from drawings made by the 

 camera lucida. Unless otherwise explicitly acknowledged, 

 all the illustrations, whether in the text or the plates, are from 

 original drawings of my own ; and I have to return my best 

 thanks to my friend Mr Berjeau for the care and fidelity with 

 which he has reproduced these on wood and stone. 



I have, finally, to express my gratitude for the varied and 

 valuable assistance which has been freely accorded to me by 

 my friends Mr R. Etheridge, F.R.S., Mr R. Etheridge, jun., 

 F.G.S., Mr George Jennings Hinde, F.G.S., Dr Gustav 

 Lindstrom, and Dr Ramsay H. Traquair, F.R.S.E. 



UNITED COLLEGE, ST ANDREWS, 

 September 10, 1879. 



