dynoderma dyn·o·derma a slender, membranous musclelike structure, believed to represent a cross between a cranium and the external spaces of fish and inverteb

dynoderma dyn·o·derma a slender, membranous musclelike structure, believed to represent a cross between a cranium and the external spaces of fish and invertebrates, supporting the glans in most vertebrates "a dynoderma is thought to have existed in all living organisms"