FAUXA OF THR AFIlICA>r I.AKES. 575 



An exaniiiiiitioii of the table of distribution sngoosts in tlie 

 lirst instance tliat there are cei-ta.ih ,yaps in the list which future 

 investigation will surely fill. It is strange, for example, that no 

 represeuta.tives of the Naidoniorpha have been found in Tangan- 

 yika, or in the smaller lakes, for it does not seem likely that 

 they are entirely wanting. Secondly, it is clear that very few of 

 the forms enumerated have been observed in more tlian one 

 lake, half of them being classed as endemic. Out of a total of 

 14 species, the highest number recorded from a single lake is 

 G (Victoi'ia ISTyanza). 



Thei'e is no indication in this case of a marked pi'e-eminence 

 for Tanganyika, either in the number or peculiarity of its forms. 

 La,ke Victoria, leads the way with 6 species, 4 of which ai-e 

 endemic, Tanganyika coming second, with exactly half that 

 number (3 in all, 2 endemic). Lake Kivu also contains an 

 endemic form. The species ai-e distributed amDng a large 

 number of genera (nineX only two of which — Pygmceodrihis and 

 Alma — are represented by more than a, single type. Lake 

 Victoria again heads the list with representatives of four genei'a, 

 Tanganyika and Nyasa coming next, each with three. No 

 endemic genera occur. 



It would serve no good purpiose to review in detail the distri- 

 bution of the different genera, and species, but reference may be 

 briefly made to the nature of the Oligochaite fauna of each 

 lake. Tanganyika alone contains a member of the Alluroidida^, 

 This worm — Alluroides tanganyikce — was first described from 

 Ta.nganyika, but has since been obtained from Rhodesia in the 

 neighbourhood of the Victoria Falls. Two endemic species 

 of Ocnerodrilinpe complete the list : there are no Naids or 

 Oi'iodrilines known. — In Victoria Nyanza the types are more 

 uniformly distributed among the families concerned. Of four 

 endemic species, two belong to the genus Pygmceodrilus and 

 one each to Atdoj'yhorus and xilma. — From Nyasa only three 

 Naid genera of wide range are on record. Pristina lovgiseta, 

 wliich I collected in that lake, is the only worm in the list which 

 occurs outside the continent of Africa, being known both from 

 Europe and America. It is strange that other aquatic Oligo- 

 chajtes have not been forthcoming from this lake as a result of 

 its careful exploration by Fiilleborn. — Lakes Albert and Kivu 

 each contain but two species. Two forms of Pygmceodrihis 

 (one endemic) come from Kivu, with one Pygmceodrihis and 

 an Ahna from Albert. No Naids have so far been observed. 

 These lakes, together with Lake Edward, have recently been 

 visited by the Gei^man Central Africa Expedition, and it is. 

 therefore, the more surprising that no Oligochaete worms have 

 been found in Lake Edwai-d. 



HiRUDINEA. 



There is but little known of the leeches which inhabit the 

 great lakes of Central Africa : indeed, there appears to be only 

 a single published record concerning them, which is that of 



