East African original material from which Otto Müller had described more than 100 new diatom taxa at the beginning of the 20th century was re-evaluated. In this paper nine of his names of Surirella taxa have been assigned lectotypes. For three taxa specimens were chosen from the original samples, for six taxa Müller's drawings have to serve as type, for three of these also an epitype is designated. Three taxa are elevated to species rank (S. tumida, S. likomensis, S. africani-orientalis), for the latter two species substitute names are validated. One taxon is synonymized. The distribution of the eight accepted taxa in East Africa is summarized from literature. Although rare, all but one have been recorded after Müller's first description. In addition to the above mentioned, these are S. brevicostata, S. linearis var. elliptica, S. margaritacea, S. turbo; only S. panganensis seems to be so rare that it has never been recorded since its first description.