This paper characterizes the electric discharges of the recently described mormyrid Mormyrus subundulatus Roberts, and is presented as a companion to the species description (Roberts, 1989). M. subundulatus was shown to differ significantly from its sympatric congener, M. rume, in several features of the electric discharge. The use of electric characters in systematic studies of the Mormyridae is discussed. Ecological data are also presented on these two Mormyrus forms, for localities in the Bandama River Basin, Côte d’Ivoire.