This study deals with the entirely terrestrial genera of southern African geckos. Of this group one new genus and two new species were described since the last complete account of the African geckos was published by Loveridge in 1947. Two new subspecies are described in this paper. Morphological descriptions, more detailed than before, are given. The population variation of Ptenopus is analysed. Basic aspects of the ecology and the zoogeography of all the species and subspecies are discussed. An attempt is made to establish the phylogenetic and taxonomic affinities of these genera. The results of this investigation are to be published in five parts in this journal. Keywords: Burrowing geckos, Gekkonidae, Morphological descriptions, New subspecies and Reptilia.