PREFATORY NOTE 



The following pages, constituting the Fifth Volume of the Memoirs of the 

 Carnegie Museum, embody the results of the investigations made by Dr. C. H. 

 Eigenmann upon the piscine fauna of the rivers of British Guiana. 



Having been granted temporary leave of absence from the Indiana State Uni- 

 versity, where he is the Dean of the Graduate School, Dr. Eigenmann went to 

 British Guiana in the fall of 1908, having the assurance of the financial support of 

 the Carnegie Museum, both in meeting the expenses of his expedition and in pub- 

 lishing the results thereof. The typical portions of the collections made by him 

 are preserved in the Carnegie Museum, including all unica. A second set, includ- 

 ing, so far as possible, cotypes of the new species, was reserved for the Indiana 

 State University. It has been arranged to dispose of the remainder of the collec- 

 tion by exchange with the leading museums of America and Europe. 



The Editor, in presenting this work to the scientific public, is animated by 

 the hope that it may prove of value to the students of biology in all parts of the 

 world, and tend to shed at least a little light upon some of the countless problems 

 which confront the student of vital phenomena. 



W. J. Holland. 



Pittsburgh, Dec. 1, 1911. 



