Proposed as a subgenus of Parvamussium. Type species (by original designation): Amussium caducum E. A. Smith (1885: 309). Name first published as a nomen nudum by Oyama, 1951 [25 February], Illustrated catalogue of Japanese shells, 1(11): 69 and later by Oyama, 1951 [15 June] Illustrated catalogue of Japanese shells, 1(11): 81 as a new subgenus, however in the meanwhile the name was validly published by Habe, 1951 [28 February] Genera of Japanese shells, 1: 71 (attributed to Oyama) with a description in Japanese, which renders Oyama's second publication (with English description) superfluous from a nomenclatural standpoint.