Colony an upright fixed anthodete’ ; the syndet6 divisible into a stout, barren, smooth stem, from the top of which a few branches, also smooth, are given off; these, after a short course, divide, and the tertiary branches thus formed subdivide into terminal twigs, on which the anthocodiae emerge. The main stem, branches, and branchlets composed of elongate longitudinally-disposed anthosteles, the more superficial of which appear as longitudinal ribs on the surface. The anthocodiae may be shortly pedicellate or subsessile; their arrangement on a branchlet may be either spicate or racemose. Spicules minute, usually of three kinds :--1. Elongate fusiform, with more or less prominent warty projections; found in all parts of the anthodet6, except at the extremities of the tentacles, and interlaced in an irregular manner to form a feltwork, specially abundant in the partitions between the anthosteles of the stem. 2. Modified double four-rayed stars, confined to the outer wall of the stem, each star sending a prolongation of one ray inward. 3. Scale-like or flattened branched spicules exhibiting a fine sculpture on their surfaces, confined to the distal parts of the tentacles and their pinnules. The anthocodiae not retractile, but the tentacles can be tightly folded over the wide oral disc, their bases thickly beset with spicula, forming by their apposition a rudimentary anthopoma. The oral disc spacious, cup-like ; the mouth, generally narrow, leads into a stomodeurn, wide and nearly circular in section in its upper moiety, tapering below to form a narrow, compressed, richly ciliated tube. The zooids so oriented that their sulcar (ventral) aspects are abaxial, their asulcar (dorsal) aspects axial.