Forbes & Hanley regarded M. denticulata and M. myosotis as fully marine and brackish varieties of a single species. They used the name Conovulus denticulatus for specimens with many apertural protruberances within the palatal (outer) lip from full marine salinity sites (on left above), and C. denticulatus var. myosotis for those with one or no protruberance on the palatal lip from brackish sites (two images on right).
They wrote:
“After a protracted examination we have decided upon uniting the Auricula myosotis of Draparnaud to the Voluta denticulata of Montagu. As many conchologists will dissent from this conclusion, we have scrupulously kept apart their description and synonymy.”
The relationship, separate species or ecotypes, between M. myosotis and M. denticulata is still uncertain. WoRMS accepts them as two species, so the precautionary course of Forbes & Hanley is followed in this account.

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