PREFACE. 



The present volume completes the description of the genus Porif,^^, and contains 

 also a descriptive list of Gonioporce, supplementary to that given in Vol. IV. 



The Museum collection is not extensive, and from the Atlantic basin there 

 are only about oO forms of Porites. A number, however, not in the collection, 

 have been described by other naturalists ; in order to study some of these, and 

 especially the types of Lamarck, the Author paid a visit to Paris, where he 

 received the most courteous assistance from the officers in charge, and especially 

 from Dr. Gravier ; later on, that gentleman most kindly superintended the 

 preparation of a series of photographs of some of the more important types in 

 the Paris Museum for this volume. 



The volume has been edited by Mr. F. Jeffrey Bell. He has in this 

 volume left the Author's observations and modes of stating them much more in 

 the Author's original words than in previous volumes, feeling that, as this is the 

 last volume which will be published with the method of nomenclature here 

 adopted, it is only right that the Author should express himself in his own way. 



The genus appears to be comparatively recent, and this may be the 

 explanation of the paucity of fossil types. Mr. Bullen Newton, of the 

 Geological Department, has afforded Mr. Bernard all the advice and assistance he 

 required. 



E. RAY LANKESTER. 



British Museum {iVatural Hidon/), 

 Cromwell lloud, 



L( I It do II. S. Jr. 

 October 11th, 1906. 



