Subgenus (Kalayoldia) U. S. Grant & H. R. Gale, 1931

(3-6-1-0-3-14-1-7-3-0-0-0-0)
Ref. Bernard, 1983 p 13
Vaught, 1989 p 114

cooperii W. M. Gabb, 1865
(3-6-1-0-3-14-1-7-3-1-0-0-0)
Syn. Nucula (Nucula) impressa T. A. Conrad in J. D. Dana, 1849, not J. Hall in Fremont, 1845, not G. B. Sowerby, 1842
Yoldia (Yoldia) cooperii W. M. Gabb, 1865;
Yoldia (Yoldia) tenuissima Clark, 1918
Ref. Bernard, 1983 p 13