Polysyncraton rostrum Monniot F. & Monniot C. 1997

This species covers rocks and corals in crusts as broad as 30 cm but only 1 to 2 mm thick. Its colour in life is light to deep orange-red (pl. IF), lighter around the common cloacal apertures. The upper surface is raised into many small and regularly spaced elevations where the common cloacal apertures open (pl. 1F). The darker oral siphons give a spotted design to the colony surface. The spicules are dense throughout the whole thickness of the easily broken crusts. The upper layer of the colony can be delaminated at the level of the thoracic cloacal channels. The basal part of the colony is the thickest and contains abdomens and larvae. The zooids have funnel-like oral siphons with sharp lobes, three short lobes alternating with three longer ones (fig. 8E). This arrangement is apparent under magnification because the tunic around each of the three longest oral lobes contains spicules that protrude as three teeth into the oral aperture. The cloacal siphon is prolonged anteriorly as a little beak with a tiny round, button-like languet (fig. 8E). This languet is larger near the common cloacal apertures. The lateral thoracic organs lie at the level of the first row of stigmata (fig. 8E), which has eight to ten stigmata. The thorax has a straight, wide base without a retractor muscle (fig. 8E). The abdomen is less voluminous than the thorax. The digestive tract has the usual shape; inside the loop are five to six testis vesicles pressed to each other in a spherical mass encircled by two to three turns of the sperm duct (fig. 8F). The gonad protrudes from the gut loop. In one colony dark cells were present in the abdominal body wall. The larval trunk (fig. 8G) is 600 p.mlong. The three adhesive papillae are surrounded by 16 to 20 ampullae in a circle; these ampullae have irregular, more or less deeply indented tips. An ocellus and an otolith are present, as are three rows of already pierced stigmata. There is a bud on each side of the larval trunk (fig. 8G). The spicules (fig. 7C, D) have very different sizes. The largest are about 40 p.m across. Their rays are numerous and usually pointed, not regularly arranged, and they are present in variable number, and may even be truncated to form balls.