As nouns the difference between serpula and serpulae

is that serpula is any of numerous species of tubicolous annelids of the genus Serpula and allied genera of the family family: Serpulidae that secrete a calcareous tube, usually irregularly contorted, but sometimes spirally coiled, with a wreath of plumelike and often bright-colored gills around its head, and usually an operculum to close the aperture of its tube when it retracts while serpulae is plural of lang=en.