FAUNA OF THE AFRICAN LAKES 



521 



Kyanza and Edward Nyanza. Although Tanganyika has certainly 

 received a considerable amount of attention, this circumstance 

 would not alone suffice to explain the relative lichness of its 

 Ophidian fauna, which is the more remarkable in that two of the 

 ^^pecies are endemic forms. It is hardly among the snakes that 

 types characteristic of a lake would be expected, but they never- 

 theless afford an interesting parallel to the state of affairs wdiich 

 is so constant and striking in most of the groups of typically 

 aquatic animals. 



Ohelonia. 



Five species of aquatic tortoises come within the scope of this 

 .survey*, of which four have been found in Tanganyika. 



1. Sternothcerus sinuatus. 



A foim well known from Tanganyika and obtained by Stuhl- 

 mann in the Victoria Nyanza (192, p. 4). It has more recently 

 been reported from Nyasa (193, p. 583) and from Lake Albert 

 (180, p. 200), while it is widely distributed in South Africa and 

 in East Africa south of the equator. 



2. Sternothcerus derhianus. 



This species appears to be more especially West African, but 

 also occurs in Tanganyika. 



3. Sternothoirus nigricaus, 



A specimen of this tortoise from Usumbura, Lake Tanganyika, 

 is referred to by Sternfeld in his report on the reptiles of the 

 German Central Africa Expedition (180, p. 201). It is also 

 known from the region of Mozambicjue and from Madagascar. 



4. Pelomedasa gcdeata. 



This is likewise a widely distributed form, and is recorded by 

 Tornier (193, p. 583) both from Tanganyika and Victoria Nyanza. 

 It has again been reported from Victoria Nyanza by Sternfeld 

 (180, p. 201), and the British Museum also possesses a specimen 

 from that locality. The species does not seem to have been 

 mentioned hitherto from any of the other big lakes, although it 

 is well known from Southern and Tropical Africa and occurs 

 -even as far north as the Sinaitic Peninsula. 



5. Cycloderma frenatiim. 

 This w ell-known Zambezi type has been collected by Fiilleborn 



* Particulars of these Clieloniaus will bci found ia the British Museum Catalogue 

 (19). 



Proc. Zool. Soc— 1920, No. XXXV. 35 



