Hydroclathrus сlathratus

Thallus creeping or free lying, fleshy, cushion-like, subspherical or irregularly lobed, hollow, 10-30(-100) cm in diam., light brown, brown to orange, with numerous perforations. The perforations round to oval, 5.0-20(-30) mm in diam., with inrolled margins. Net-like membrane consist of 3-6 cell layers, 500-900 μm thick. The cortex composed of 1-2 rows of pigmented, small cuboid cells to 10 μm across. Medullary cells colorless, large, rounded angular, 50-130(-180) μm diam. Holdfast inconspicuous, lightly attached at many points. Hairs in groups develop in shallow surface depressions. Growing in sheltered areas on lower intertidal to shallow subtidal dead corals, rocks, pebbles and epiphytically.

Tropical and subtropical waters of Atlantic, Indian and Pacific Oceans. Common in countries of the Asia-Pacific Region: Japan, China, Korea, Vietnam, Philippines, Thailand, Malaysia, Singapore, Australia and New Zealand, Pacific Islands.