This is a species having a remarkable morphological variability, that can be easily confused with its congenerous one H. rugosa (Linnaeus, 1767). Recent studies (see bibliography) showed that the morphological differences between the two species, stated by B.D.D. (1896), cannot be generally applied. While, as explained in the note concerning H. rugosa, the difference in the cardinal margin is considerable. There are also other not much important differences in the sizes and in the prodissoconch sculpture: H. arctica has got a little bit bigger diametre and some concentric striae at the margins, no present in H. rugosa. There were described several variety names as: inermis, praecisa, dilatata, oblonga, abbreviata etc. of no taxonomic value. The average measures are abt. 10 mm.

Very common all over the Mediterranean. It lives in a few metres depth up to remarkable depths. Habitat: it lives, anchored by its byssus, to solid substrata, with some bivalve molluscs too, tubes of polychaetes and to artificial material employed in the mollusc culture.