PREFATORY NOTE 



TO EIGHTH EDITION. 



The present edition is printed from the same plates as 

 the fifth edition, published in 1890. The decade which 

 closes the century has seen greater activity in the study of 

 species of animals and their relation to their environment 

 than has been known in any other corresponding period 

 in the world's history. Such study has given much greater 

 precision to our knowledge of the characters and the dis- 

 tribution of species, with the minor results of the recogni- 

 tion of synonyms, and the correction of nomenclature by 

 its establishment on the solid basis of priority. 



Most of the recent changes in the scientific names of 

 animals are due to the use of the earliest name given to 

 the species, instead of some later one applied through 

 error of one sort or another. 



To bring the present work up to date, it is necessary to 

 change these antedated names, but there is no correspond- 

 ing change, in most cases, in the definitions of the genera 

 and species themselves. It has therefore seemed unneces- 

 sary to ask the publishers to incur the great expense of 

 resetting the type for a new edition. I have indicated in 

 an appendix the principal additions and alterations which 

 seem necessary in the group of Fishes. By the applica- 

 tion of these corrections the nomenclature of this group 

 will be made to correspond to that of Jordan & Ever- 

 mann's Eishes of North and Middle America (4 parts: 

 part 1, published 1897 ; parts 2 and 3, 1898 ; part 4 in 

 1899), to which elaborately illustrated work students are 

 referred for further details. 



