The Sumba-Expedition undertaken by Dr. E . Sutter of the Naturhistorisches Museum of Basle and Dr. A . Bühler of the Museum für Völkerkunde of the same town, visited the Lesser Sunda Islands, Indonesia, in 1949. Dr. Sutter, the zoologist, stayed in the islands from 19 May to 26 November; most of the time was spent by him in Sumba (21 May-31 October), and extensive collections were made there, among which a most interesting material of Decapod Crustacea, which forms the subject of the present paper. A few Crustacea were collected on the islands of Sumbawa (on 19 May) and Flores (19 and 21 November). The animals taken at Flores belong to species also obtained in Sumba and will be treated here with those; at Sumbawa two hermit crabs belonging to the species Clibanarius longitarsus (De Haan) were collected in the mangroves near Sumbawa Besar, these specimens inhabited the shells of Melanoides tuberculatus (Müller) and Melanoides plicaria (Born) (identif. W. S. S. van Benthem Jutting), they are not further considered here.