in taxon Echinodermata papula papulli A thin protuberance on the surface of the body of an echinoderm containing diverticula of the water vascular system lined by ciliated peritoneum. Along with tube feet, provide the principle gas exchange surfaces.. 2009-04-18T01:13:57Z Wikipedia:Papula papulae UBERON:0000205 gill Christopher J. Mungall