Free-living species generally consisting of a large single polyp.  Reproduces sexually or asexually, by budding from the remains of an old polyp and fission.  Young polyps are attached by a stalk to the parent, breaking free as they increase in size.

Sharkfin, Lana'i, 80 feet

Pearl & Hermes Reef, NWHI, 35 feet

Sharkfin, Lana'i, 80 feet

Sharkfin, Lana'i, 80 feet

Kewalo Pipe, Oahu, 55 feet

Round with six prominent septa (ribs), bottom is slightly convex at the center.  Uncommon on sand in deeper water.  Often has bright orange or green fluorescent color.  Small polyps are hexagonal.

Angel Ledge, Midway Atoll, 80 feet

Fission, Pearl & Hermes Reef, 50 feet

Kaka'ako, Oahu, 55 feet

Newly reported from Hawaii; long confused with other species.  Round with septa (ribs) of uniform size, bottom usually concave.  Frequent in the Northwest Hawaiian Islands upon hard reef.

Sharkfin, Lanai, 25 feet

Parasitic Wentletrap snail w/eggs on underside, Kaneohe Bay, Oahu, 3 feet

Moku o Loe, Kaneohe Bay, Oahu, 2 feet

Moku o Loe, Kaneohe Bay, Oahu, 2 feet

Moku o Loe, Kaneohe Bay, Oahu, 2 feet

Moku o Loe, Kaneohe Bay, Oahu, 2 feet

Makapu'u, Oahu, 25 feet

Puako, Hawaii, 20 feet

Common in reef depressions in shallow water.  Generally oblong and thick with sinuous ribs of varying length.  Tentacles may be green when extended.  Preyed upon by Epitonium ulu, an endemic Wentletrap Snail.

Puako Bay, Hawaii, 70 feet

Puako Bay, Hawaii, 70 feet

Puako Bay, Hawaii, 70 feet

Waimea Bay, Oahu, 35 feet

Rare on coarse sand in deep water.  Septa are of equal height at the outer edges.  Segments break off readily.

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