PRE FACE. 



'J'liE scope of Volume IV. of the present Catalogue is in accordance 

 with the anticipation expressed in the Preface and Introduction of its 

 predecessor. Three Suborders are first considered, namely : the Acan- 

 thopterygii, eight Families of which were dealt with in Volume III. ; 

 the Opisthomi, represented by the MastacembelidiB ; and the Plecto- 

 gnathi, similarly including only one Family, the Tetrodontidte. Tlie 

 subject is then continued by an account of addenda to tlie previous 

 volumes. The danger of overlooking these has been minimised by tlie 

 preparation of a general systematic index to the four volumes, in wliich 

 tile author h;is ])laced the new species in what he regards as their 

 jiroper position in his system. 



Mr. Boulenger's account of the Fresh-water Fishes of Africa is thus 

 brought to a conclusion, ^^'llile recognising fully the value of the 

 services rendered by the collectors and donors of unique material 

 preserved in the Museum, and particularly by those mentioned in tlie 

 Introduction, it is impossible to overlook the fact that the principal 

 stimulus leading to the acquisition of the collection has been tlie 

 author's own enthusiasm and unrivalled knowledge of the subject of 

 this wdik. 



liiiiTisii ifisiXM (Xaiuhai. History), 



I,l>\lici\. 



Jamiitiii, I'.llG. 



SIDNEY F. HAK.MER, 

 Keeper of Zouhynj. 



