This taxon is inactive. It has been synonymized with Fiocuthona concinna.https://www.marinespecies.org/aphia.php?p=taxdetails&id=1832622

Cuthona distans is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Fionidae.Gofas, S. (2014). Cuthona distans Odhner, 1922. Accessed through: World Register of Marine Species on 2015-02-12.

Distribution This species was described from the Varangerfjord, near Vadsø in Finnmark, Norway. However, this nudibranch has not been seen since it was first described by Odhner in 1922.Evertsen J., & Bakken T. (2005). Nudibranch diversity (Heterobranchia, Gastropoda) along the coast of Norway. Fauna norvegica 25: 1-37

References