Phenacolepas crenulatus: Almost round, of variable height, apex recurved and located at the anterior third position; sculptured with many finely nodulose radial cords and concentric striae; interior with a narrow rim near the margin. Exterior cream; interior white.b2.5 cm. Indo-West Pacific; Dampier, WA to Moreton Bay, Qld. Synonym: mirabilis Sowerby, 1910.

In the first part, I followed other authors , keeping the australian PL mirabilis Sow. separated from cytherae (= crenulata). Sowerby considered mirabilis (25 x 22 x 8 mm; H/L = 0.32, loc. Australia?) as a valid species, more depressed than crenulata, with the apex less curved, less posterior, at 1/3 of the length, having "the concentric lirae rather distant towards the apex", a characteristic which I consider very typical for cytherae. Cernohorsky, 1972, considered mirabilis as dubious but my Australian friend Ivan Marrow, a great shell collector to whom I am much indebted, recently sent me some specimens from Queensland (one with less concentric ribs, from Yeppoon) and considered in his letter mirabilis as synonym of crenulata.
Having now seen a typical cytherae in the collection of G. Trappe, very big and depressed (30 x 26 x 10 mm on my copy), without pronounced radial ribs, I admit the identity of both and consider mirabilis, created by Sowerby five years after his nobilis (kept separated by Thiele from crenata because of its height), as a new synonym of cytherae, a not common species, widely distributed and having H/L variations between 0.32 (mirabilis) and 0.61 (nobilis). The H/L values of the three crenulata, drawn by Thiele, are 0.48, 0.54 and 0.59. This fact doesn't change the distribution, as Queensland was already mentioned in Part I, where I identified a specimen from Lizard Isl., seen in the USNM, as cytherae. The southern limit, known by me, is the Tropic of Capricorn (Keppel Bay, Yeppoon) where the specimens reach big dimension. I show (fig. 30.a) the pronounced ribs of a typical mirabilis, 27.8 x 25 x 11.2 from Keppel Bay, ex Mrs. Rutherford, specimen having also a large internal plate or septum on the posterior marginal border.