FAUNA OF THE AFRICAN LAKES. 577 



fishes, but some were obtained from a large Siluroid taken in 

 Victoria Nyanza. In all, these parasites were collected from 

 8 different 8pecies of fish, belonging to 8 genera and 5 families. 

 Since these fishes are, with a single exception, endemic forms, 

 it is likely that their parasitic Nematodes will prove interesting 

 and perhaps new to science. 



It does not seem logical to regard the Jscc(7'is from the Edward 

 Nyanza pelican as belonging to the fanna of that lake, and as the 

 specimens I collected have not been identified or described, the 

 only records available for the purposes of this paper are those of 

 the free-living types from Nyasa. The species which all belong 

 to the family Angnillulidse, may be enumerated as follows : — 



1. Monhystera fullehorni. 



Described as new from a single specimen in the surface 

 plankton. 



2. Monhystera vulgaris. 

 A species known previously only from Europe. Obtained near 

 the mouth of a river which enters the lake. 



3. Monhystera similis. 



Likewise recorded from Europe and found in the neighbour- 

 hood of Nyasa. 



4. Trilohus graciloides. 



This species has been described as new by Daday. It comes 

 from the vicinit}^ of Nyasa, but has also been taken on the 

 swampy shores of Lake Kukwa. 



5. Mononchus tenuis. 

 Under this name Daday described a single male specimen 

 which he found in a sample of mud brouglit from the bottom of 

 Nyasa at a depth of 200 metres. 



6. Monochus macrostoma. 

 Collected in a pool near the lake. Also known from Europe. 



7. Dorylaimus macrolaimus. 

 A European species which appears to be common in the waters 

 around Nyasa, but has not been observed in the lake itself. 



Out of a total of 7 species, 2 may be regarded as peculiar to 

 the lake fauna, while one of the remaining forms is confined to 

 East Africa. The others are known also in Europe. 



Thus there is no indication that the free-living Nematoda of 

 Nyasa are in any waj remarkable or specialised, and information 

 is not available concerning either free-living or parasitic types 

 from any of the other lakes. 



* Particulars of these will be found in Daday's monograph (76, p. 44). 



