Corallum massive, consisting of several portions superimposed over old ones, separated by thin layers of epitheca; upper surface dome-shaped.

Corallites monocentric, at most 2 centers in non-dividing valleys; most corallites monocentric. Maximum length of valleys 9-10 mm, width 5 mm; depth 5 mm. Wall very thin, less than a mm, its top sharp.

Septa in big monocentric calice around 24, 10 of which reaching columella; around 7 to a half cm, very slightly exsert over calicinal wall, those from neighboring calices oftentimes meeting exactly. Rudimentary septa in form of very low ridges or rows of spines quite common, alternating with larger ones. Septal edges regularly, ruggedly dentate, the teeth themselves being spinous. Big septa with upper two thirds narrow, vertical, almost overhanging in some; lower third conspicuously widened and thickened, usually with vertical projection (paliform lobe) at its corner; its edge also vertical but with irregular, large dentation. Septal surface laxly spinulate.

Columella poorly developed, almost absent; at most consisting of a few septal trabeculae projecting medially. Dissepiments almost horizontal, over a mm apart..

Remarks: This species resembles P. astraeformis (ME and Haime) as described by Vaughan (1918) and figured by Yabe, Sugiyama and Eguchi. It may be distinguished from the older species by its uniformly thin wall, its conspicuous paliform lobes and the presence of rudimentary septa.

Source: Nemenzo F (1955) Systematic studies on Philippine shallow water scleractinians: I. Suborder Fungiida. Nat. Appli. Sci. Bull. 15:3-84. 14 pls.