Montacuta moelleri Posselt, 1898 accepted as Mysella planata (Dall, 1885) (original description)
Nucula groenlandica Posselt, 1898 accepted as Megayoldia thraciaeformis (Storer, 1838) (original description)
Rissoa arenaria (Mighels & C. B. Adams, 1842) accepted as Onoba mighelsii (W. Stimpson, 1851) (new combination reference)
Rissoa castanea var. minor Posselt, 1898 accepted as Rissoa castanea Møller, 1842 accepted as Boreocingula castanea (Møller, 1842) (original description)
Scalaria arctica Posselt & A. S. Jensen, 1898 accepted as Acirsa borealis (Lyell, 1841) (original description)
Sipho (Siphonorbis) lindahli Posselt & A. S. Jensen, 1898 accepted as Retimohnia glypta (A. E. Verrill, 1882) (original description)
Sipho (Tritonofusus) costiferus Posselt & A. S. Jensen, 1898 accepted as Turrisipho lachesis (Mörch, 1869) (original description)
Sipho lindahli Posselt & A. S. Jensen, 1898 accepted as Retimohnia glypta (A. E. Verrill, 1882) (original description)

 Status

 for Rissoa castanea var. minor Posselt, 1898

Posselt cited an unpublished name by Møller and made an implicit reference to Rissoa (Cingula) [= Onoba] arenaria ... [details]