Ectocarpus arctus Kützing, 1843b: 289 (type locality: "Golf von Spalato'' [Split, Croatia]).
Ectocarpus siliculosus (Dillwyn) Lyngbye forma arctus (Kützing) Kuckuck, 1891: 40, 67–69.—De Toni & Forti, 1923: 83.
INDIAN OCEAN DISTRIBUTION: Australia.