Subgenus (Crassithracia) T. Soot-Ryen, 1941

(3-2-4-0-4-3-0-38-1-0-0-0-0)
Ref. Bernard, 1983 p 64

beringi W. H. Dall, 1915
(3-2-4-0-4-3-0-38-1-1-0-0-0)
Bering Thracia
Ref. Abbott, 1974 p 559
Amer. Fish. Soc., 1988 p 48
Syn. Macoma truncaria W. H. Dall, 1916
Ref. Bernard, 1983 p 64

challisiana W. H. Dall, 1915
(3-2-4-0-4-3-0-38-1-2-0-0-0)
Challis Thracia
Ref. Abbott, 1974 p 559
Amer. Fish. Soc., 1988 p 48
Bernard, 1983 p 64