THE FAUNA OF THE GREAT AFEICAS LAKES. 635 



faunas as a whole : and this isolation of a number of M«J- 

 luscan genera in Tanganyika is also shared b\' a number of 

 fishes, crabs, prawns, sponges, medusa: 

 of protozoa, none of which are ref 

 other lakes. 



It becomes in this wa} _ ^ 



fauna of Tanganyika is not only - 



complex than that of its sister jakes. Tne 1^ 

 oranvika is in fact r 

 types or gr- ~ . 



widespread 



which are those of a txp: 1 



made up of a 

 and the /!?«/ ^ 



The broac 

 the great Afr: : - 



result, that in the one ia 



at present is - 



exists to-d^' - . 

 lake, but tr 

 species, ei: :-- 



Xow, : T _ ^ - 



mind it wL. . -rv ^ 



result eflfectually 

 which were o^ver. 



the existence : : -. The 



animals in q_ - "-_ 



African lake 



restricted to t? - 



resulted frc ~ zr± t ^ 



in a OTeat lake, hz - - 



pronoi:':"' - '^^ 

 sanviki^ 



older '.:..-.:. - 



have had time to modify th±T± — e. 1 



would point out '- - 



water ^unas <rf th L 



as that of Tangac 

 geological evidec ; - ^uitv crf^ ^}~^ 



