FAUNA OF THE AFRICAN LAKES. 577 



fislies, but some were obtained from a large Silnroid taken in 

 Victoria Nyanza. In all, these parasites were collected from 

 8 different species 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 J sca^'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, tlie 

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

 tlie free-living types from Nyasa. The species *, wliich all belong 

 to the family Anguillulidfe, may be ennmerated as follows : — 



1 . Monhystera fi'dle horni. 



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 vicinity of Nyasn, but has also been taken on the 

 swampy shores of Lake Rukwa. 



5. Mononchios tenuis. 

 Under this name Daday described a single male specimen 

 which he found in a sample of mud brought 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 macrolaimiis. 

 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 fanna, while one of the lemaining forms is confined to 

 East Africa. The others aie known also in Europe. 



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

 Nyasa are in ai>y way remarkable or specialised, and information 

 is not available concerning either fi'ee-living or parasitic types 

 from any of the other lakes. 



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



