viii PEEFACE. 



been already described and illustrated in the works of Prof. Zittel, it has only been 

 necessary for the purpose of the Catalogue to give references to the works in which 

 the description of these forms will be found. The Sponges from British strata, on 

 the other hand, have not received a similar amount of attention from the paliEon- 

 tologists of this country ; and, with the exception of the forms treated of by Toulmin 

 Smith and those lately described by Prof. Sollas, no systematic endeavour has hitherto 

 been made to describe these organisms in detail ; and therefore it has been necessary 

 to supplement the meagre notices usually given, by such brief references to their 

 minute structure as will enable them to be recognized. 



I have followed in this Catalogue the classification of Prof. Zittel, the only one, 

 in fact, which is at all applicable. Limitation of space has necessitated the omission 

 of generic diagnoses, save in those cases in which new genera are introduced, or in 

 Avhich it has been needful to make emendations; and the student must therefore 

 refer for these to Zittel's ' Handbuch der Palaeontologie ' or to the " Studien iiber 

 fossile Spongien" (Abh. bay. Akad. d. Wiss., Bd. 13, 1877-78). An English trans- 

 lation of the main portion of the generic descriptions, by W. S. Dallas, F.L.S., 

 is contained in the 'Annals and Magazine of Xatural History' for 1877, 1878, 

 and 1879. 



In a few instances I have described species of which the Museum does not at 

 present possess any examples ; but these forms will be found in the Museum of 

 Practical Geology in Jermyn Street, and w^ere kindly lent for examination by 

 Prof. Archibald Geikie, LL.D., F.R.S. 



The illustrations of the minute structure will, in some cases, appear defective — a 

 result due, not to any lack of ability on the part of the artist, but to difficulties arising 

 from the state of preservation of the fossils themselves. In all cases the endeavour 

 has been to delineate the structure in its present condition. 



I regret that it has not always been possible to give the exact localities of many of 

 the Sponges from the Upper Chalk. This arises from the fact that the greater part 

 of the collection made by Toulmin Smith is without any reference to the places from 

 which the Sponges were obtained ; but it is definitely known that they were procured 

 from the counties of Kent, Surrey, and Sussex, and I have therefore catalogued such 

 specimens as from the South of England. 



GEORGE J. HINDE. 



Dkpahtmekt of Geology, British Museum 



(Natural Hisioet), 



CsoMWELL Road, London, S.W. 



