The freshwater fishes of rivers Mungo and Meme and Lakes Kotto, Mboandong and Soden, west Cameroon

" Collections of fishes from the upper Mungo and its tributaries and from Lakes Kotto, Mboandong and Soden are described and their relationships discussed. The status of Brienomyrus longianalis is examined in the light of variation within and between populations of B. brachyistius. A new species of Labeo is described. The Mungo contains two species of Barbus with parallel-striate scales, one of which is given a new name. The three small Barbus species with radiating striae on the scales are identical with those of Fernando Poo and one of them, here given a new name, is so far reported only from Fernando Poo and the Mungo and Meme systems.

In the course of comparisons with this species records of the geographical distribution of B. trispilos and B. liberiensis are critically examined and possible synonyms of B. baudoni are discussed. Specimens of Auchenoglanis from two localities prompt questions, but no answers, concerning the specific characters within this genus. Two species of Chiloglanis were collected in the stony beds of swift streams. One of them is described as new and some special features in the structure of the head in this genus are described. Seven species of cyprinodonts are recognized in the area, one, a Procatopus of Lake Soden, new. The identity and synonymy of Aphyosemion oeseri Schmidt are discussed and a new description is given of Procatopus similis Ahl.

The structure of the pharynx in Chromidotilapia is described, C. loennbergi is considered to be a subspecies of C. guntheri, a West African species present also in the Mungo together with a new species related to C. batesii. The new species is described and compared with samples from Fernando Poo and South Cameroun. The Hemichromis of the area is the 'B form of H. fasciatus', here tentatively identified with H. elongatus Guichenot. The description of Tilapia kottae is amplified and the name T. camerunensis Lonnberg is revived for a related species inhabiting the Mungo as well as the Meme and distinct from T. camerunensis Holly of the Sanaga system. T. mariae of Lake Kotto is no longer considered to merit subspecific rank. Some notes on Sarotherodon galilaeus and its subspecies are included. The Mungo-Meme fish fauna is seen as part of that of the forest zone from western Nigeria to South Cameroun, having none but the most widespread species in common with the Chad basin. Lakes Kotto and Mboandong contain a slightly modified section of this fauna and Fernando Poo harbours twelve species common to it and the Mungo and Meme systems, adapted to life in clear running water. This throws into greater relief the high degree of endemism in the crater lake Barombi Mbo "