The evolution of the arrangements for protruding the polypide seems to have proceeded along several distinct lines: (i.) In certain species of Membranipora the frontal membrane, or membranous free-wall, is protected by a series of calcareous spines, which start from its periphery and arch inwards.
periphery הגייה עם משמעויות, מילים נרדפות, הפכים, תרגומים, משפטים ועוד