Convolutidae discoid to obcordate in shape;
color results from pigments and symbiotic algae;
often with two coexisting species of algal symbionts;
brain insunk;
mouth ventral and in posterior third of body;
rhabdoids present;
ovaries and testes paired;
with sub-terminal male genital pore. Male copulatory organ composed of muscular seminal vesicle filled with sperm. Female gonopore present or absent. Seminal bursa with 2 or more (2?8) bursal nozzles. Statocyst and eyes absent in mature forms, but present in immature specimens. Frontal organ absent. Epizoic on corals.[From Ogunlana MV, Hooge MD, Tekle YI, Benayahu Y, Barneah O, Tyler S (2005)]: 9