Abditoporella dimorpha

Description. Zoarium uni- to multilaminar, encrusting gastropod shells, dead tests of sea-urchins or often on sea-urchin spines of Eucidaris thouarsii. Zooids distinct, initially longer than wide (see Table 1), with rounded, narrow distal end, broader proximally with straight, angled margins, becoming irregularly disposed, with morevariable outlines in mature colonies, separated by distinct interzooidal furrows. Frontal shield slightly convex, with rugose surface and regularly spaced pseudopores. Orifice campanuliform, longer than wide, with elongate anter separated from short, broad poster by well-developed condyles. No oral spines. Avicularia rare, small, adventitious or interzooidal, often seen near orifice, with complete crossbars; rostrum rounded, smooth, with suboval to subacute mandible. Infrequent polygonal kenozooids between autozooids, with large pseudopores and no orifice. Embryos brooded endozooidally in dimorphic female zooids with smaller orifices than non-brooding zooids; a broad zone of pseudopores, larger than frontal pseudopores, distal to maternal orifice, which has a less-rounded proximal margin. Polypides and ancestrula not seen.