FAUXA OF THE AFRICAN LAKES. 



587 



in the other l;ikes*, although Seliiiliotz states tlia.t he completely 

 failed to find any in Kivii (166, p. xiv). The species from 

 Victoria, Nyanza, a,nd Nyasa, a,rc (|uite oi'dinaiy forms, but those 

 known from Tanganyika exhibit divergences of at least specific 

 rank from the types collected in an}^ other part of the continent. 

 Of the eight species enumerated in the adjoining table, seven 

 belong to the cosmopolitan fresh-water genus Spony'dla. the 

 eighth — about which doubts ha.ve been raised — being leferred 

 provisionally to the genus Fotamolepis. 



Tahle of Distrilnition of For if era t- 



Niune of Species. 



Tano-an- 

 yiiva. 



Victoria 

 Nyanza. 



ISTyasa. 



Other parts of 

 the world. 



Family SpoxaiLLiD^. 











Spong-illa biseriata 







P 



Egj-pt. 



,, bijlnnii 



■ P§ 







E. Africa. 



„ carteri 



P 





Hungary, India, Java. 



„ cuiiniiigtoiii .. 



E 









„ nioorei 



E 









,, iiitens 



- P§ 

 E 







White Nile. 



„ taiigaii3'i]vnR .. 









Potamolepis weltiieii .. 



E 









8 species 



4E, 2 P. 



IP. 



IP. 





§ Not actnall}' recorded fi'om the lake itself, but from within its drainage area. 



Th.e distinctness of the fauna, of Tanganyika, is once more 

 exemplified in the case of the sponges, and is shown graphically by 

 the above list. W'^hile Victoria Nyanza and Nyasa each contain a. 

 single species of somewhat extended distribution, Tanganyika 

 contains six other types, four of them (those occurring in the 

 waters of the lake itself) being endemic. 



The forms from Lake Victoi-ia and Nyasa, l)oth of ^^ hich were 

 o1)tained for the first time by my expedition, do not call for much 

 comment. Spongilla cartfiri, now known from Victoi-ia- Nyanza, is 

 tlie only sponge fi-om the lakes to occur outside the continent of 

 Africa. While it occurs in Europe, its occurrence also in India and 

 Java, is noteworthy in view of the alFmities of other African and 

 Indian types to which I'eference has already lieen made. Five 

 species of Spongilla have been recognised from the Tanganyika 

 area, three of them — all endemic — from tlie lake proper, and the 

 remainder from the Ugalla Kiver, a tributary of the Malaga.rasi, 

 which in its turn enters the lake. The forms from the Ugalla 

 River, S. hdhmii and S. nitens, occur also in other parts of Afiica, 

 FoUowing the usual procedure, from which it is perhaps illogical 

 to depart, these species are inserted with an explanatory footnote 

 in the Tanganyika column, but it may be pointed out that the 



* Sponge spicules were observed by West in tow-nettings made in Albert Nyanza 

 (201). it is probable that these occurred in the sample obtained from near the 

 bottom in about 30 feet of water. 



t The principal source of information on this group has been Kirkpatrick (105) • 

 where references to other authors are given. 



39* 



