Monostroma pulchrum Farlow, 1881: 41 (syntype localities: Watch Hill, Rhode Island; Gloucester, Massachusetts; Portland, Maine, U.S.A.).—Weber-van Bosse, 1913a: 48.
Protomonostroma undulatum (Wittrock) Vinogradova forma pulchrum (Farlow) Wynne, 1986b: 64: 2264.
INDIAN OCEAN DISTRIBUTION: Indonesia (Lombok).
Note: When Vinogradova (1969: 1354) first proposed the combination Protomonostroma undulatum, she did not cite the place of publication of the basionym (Monostroma undulatum Wittrock, 1866: 46–48, pl. III: fig. 9; type locality: Nordland, Norway) and thus failed to satisfy Art. 33.2. This shortcoming was rectified by the author in a later work (Vinogradova, 1979: 104).