Halecium dyssymetrum Billard, 1929

Hydrorhiza tubular, crumpled, loosely reptant on substrate.

Stems simple, unfascicled, unbranched, internodes smooth, somewhat geniculate, nodes a transverse constriction in perisarc. Primary hydrotheca sessile, distal on internode, pedicel of secondary hydrotheca (if present) arising from diaphragm of primary, perisarc with several constrictions, widening distally to the diaphragm.

Hydrotheca deep bowl-shaped, symmetrical, perisarc thinning at margin. Margin entire, circular, rim slightly everted. Diaphragm pronounced, thickened at junction with the hydrothecal wall, the thickening greater on abcauline side; a few small desmocytes visible above the diaphragm in some hydrothecae.

Hydranth with 24 stubby tentacles, webbed at base, too large to retract into hydrotheca.

Colour: Yellow to white.