In The British species of Lamellaria. J. Conch. Lond., 21, pp.170-173, (1939), N.F.Mcmillan wrote, “latens is always smaller, and usually - - - minutely freckled with dark brown or black; perspicua (adult) is usually larger, and always of some shade of lilac-grey. Not speckled - - - .” She added, “These statements may not hold good everywhere,”. Since then, it has been shown that some pale examples of L. perspicua have markings, including black speckling, very similar to those attributed to L. latens, and that L.perspicua has many colour forms other than lilac-grey.
Her watercoloured sketch shows the fine black speckling she attributed to L. latens, and the lilac-grey she describes for L. perspicua.