Codium arabicum

Thallus spongy, lubricous, leathery, contorted, prostrate, flattened or forming irregularly lobed mats or cushions, dark green to blackish green, 3×7 cm across. Utricles nearly cylindrical, club-shaped, slightly constricted below the apex, firmly connected and difficult to separate, 60-300(-400) mm diam., (300)-650-800(-1170) mm long. Apex broadly rounded or flattened. Apical wall very thin, indistinct, to 1.5 mm thick. Hair scars on older utricles, in band, 80-125 mm below the apex. Gametangia at sides of utricles, oval, 240-270 mm long, and to 110 mm diam. Rhizoids fine, 17-25(-30) mm diam., very long, to 2 mm. Growing on stones, dead corals, tightly adhering to the substrate in middle and lower intertidal.

Widespread in tropical and subtropical waters of Indian and Pacific Oceans.