PKEFACE 



Owing to unforeseen circumstances, not unconnected with the 

 foundation of a new University, the publication of this -volume 

 has been unduly delayed. Some parts of the work have a(;tually 

 been in type for more than four years ; and although the authors 

 have made every effort to keep them up to date, the arrangement 

 is naturally not quite what it miglit have been if the articles 

 had been written immediately before publication. 



In view of the novelty of Mr. Boulenger's classification of 

 the Teleosteans, and of the fact that several independent workers 

 have been occupying themselves with the subject during the 

 last year or two, it is fair to state that this part of the volume 

 was completed in 1902. Professor Herdman's account of the 

 Ascidians was ready for publication two years earlier. 



Professor Bridge wishes to express his best thanks to Dr. 

 E. H. Traquair, P.K.S., for his kindness in reading the proofs of 

 the pages which deal with the fossil Crossopterygii, Chondrostei, 

 Holostei and Dipnoi, and for much helpful advice and criticism ; 

 to Mr. Gr. A. Boulenger, F.E.S., for his valuable and suggestive 

 criticism on certain points ; and to Mr. Edwin Wilson, for the 

 care which he has taken in the preparation of the figures. 



July 1904. 



