532 DR. W. A. CUNNINGTON ON THE 



The family Cyprinidse is better represented than the others 

 hitherto considered, but this is mainly due to the number of 

 species of the very widely distributed genus Barhiis, of Avhich 

 about 250 forms have been a,lrea,dy described from the fresh- 

 watei'S of Africa. There are types of this gfenus pecnlia.r to each 

 of the lak:es under review with the exception of Lake Albert, in 

 which, strange to say, no representative has yet been found.. 

 The genus Varicorhinus, found in Asia and various parts of 

 Africa, occurs in the lakes only in Tanganyika, where there- 

 are two characteristic species. It is noteworthy of the genus- 

 EnyrauUcypris that each of the three big lakes appears to contain 

 a form peculiar to itself. 



The family Siluridte cannot be expected to afibrd evide;;ce of 

 much value concerning geographical distribution, since many 

 of its members can remain for prolonged periods out of water 

 and even progress for some distance over land. There are there- 

 fore few points of significance to which attention need be drawn,, 

 but it may be pointed out that even in this group, Tanganyika 

 exhibits two endemic genera, h'urther, it is curious to note that 

 the genus Ghrysiclithys, while common in the Nile and Tropical 

 Africa., occurs in Tanganyika alone, in Avhich six of the seven 

 species named are likewise endemic. 



Only a. few types of the family Cj'prinodontida^ are represented 

 in the list, but among them is Lamprichthys, a genus peculiar' to- 

 Tanganyika. — The genera Lates and Luciolates are the only 

 members of the Serrariidte to be found in the big lakes, and of 

 the species which occur, only one — the well-known Lates niloticus 

 — appears outside the conrines of Tanganyika. Thus in this. 

 group also there is a genus {Luciolates) endemic in that lake. 



While the families hitherto considered show various noteworth}^ 

 features of distribution, it is the Cichlidje which far surpasses 

 them all, both in interest and in the number of forms represented 

 in the African lakes. Of all the species enumerated in the table- 

 of distribution, more than 70 per cent, are Cichlids, or to put it 

 another way, tliere are considerably more species of the family 

 Cichlidte than of all the other families taken together. In the- 

 case of the genera,, exactly half are Cichlids, there being 36 out 

 of a total of 72. These are remarkable facts, but they are not 

 merely an expression of the common occurrence of this group of 

 fishes on the continent, as an examination of the list will show. 

 It is quite clear that there ai-e groups of forms which ai'e peculiar 

 to these big la.kes, and that the three biggest contain more 

 than the smaller ones, while a, culminating point is reached in 

 Tanganyika, with a succession of endemic genera. 



Lake Albert is alone in containing no endemic species, but the 

 numbers grow from 2 and 3 endemic forms in Lakes Kivu 

 and Edward respectively, to 31 in Nyasa, 40 in Victoria, Nyanza, 

 and no less than. 84 in Tanganyika. Nor is this all, for in the 

 number of endemic Cichlid genera the remai'kable nature of' 

 the fauna of Tanganyika is particularly exemplified. In the 



