CHAPTER VII. 



GENERAL OUTLINE OF THE ZOOLOGY OF THE GREAT 

 AFRICAN LAKES. 



In order that a general appreciation of the nature of the 

 Tanganyika problem may be obtained, I have prefaced the 

 more detailed examination of the components of the fauna 

 of the lake, with an account, or rather with a series of 

 enumerations, of the different animals which have hitherto 

 been recorded in each of the other great African lakes. By 

 this means certain features of the distribution of the fresh- 

 water fauna of equatorial Africa are rendered self-evident, 

 and numerous repetitions which would otherwise be 

 necessary in the sequel can be avoided. But besides this, 

 so much that is new has recently been added to our 

 knowledge of the composition of the faunas which exist 

 in the great African lakes, that it is now for the first time 

 possible to deal with the general characteristics of the 

 equatorial African fresh-water fauna, and the results of such 

 a study lead not only to conclusions which are interesting, 

 but which are also by no means without importance from 

 the broader biological point of view. 



There are thirteen great African lakes, about the fauna 

 of which it can be said that something definite is known 

 at the present time. 



