In April 1980, Mr. P. Planquette of the Laboratoire d'Hydrobiologie, PetitBourg, Guadeloupe, presented me with a collection of naked catfishes from French Guiana, which he had brought together in the course of an ichthyological survey of that country, carried out between September 1978 and March 1980. The survey continues and in September 1981 a few additional specimens were received from Mr. R. Rojas-Beltrán, who is collaborating with Mr. Planquette in the project. The material consists of 19 species belonging to six families: Auchenipteridae (six species), Aspredinidae (one species), Pimelodidae (nine species), Helogeneidae (one species), Trichomycteridae (one species) and Cetopsidae (one species). The Aspredinidae are represented by a single specimen belonging to the genus Bunocephalichthys (RMNH no. 28577). As, in spite of useful short reviews by Myers (1942, 1960) and Fernández-Yépez (1953), the systematics and nomenclature of the Bunocephaline catfishes are greatly confused, a discussion of this specimen is reserved for inclusion in a paper on the fishes of this group, on which I have been working for some time. The one specimen of Trichomycterus (RMNH no. 28605) and the two specimens of Cetopsidae (RMNH nos. 28606, 28607) have not yet been identified and will not be further dealt with here, except to say that the former belongs to a species that is common and widely distributed in Suriname. Of the other species, several are new to French Guiana, but their occurrence is not unexpected as they were already known from adjacent Suriname, apart from one which appears to be undescribed. All the collecting-localities are shown on the accompanying map (fig. 1). To facilitate comparison with my publication on certain Nematognathi from Suriname (Mees, 1974), it should to be pointed out that the Dutch name for the