protulae

Updated: May 27, 2025

Here the supposition at once presents itself that the primitive tubicolar worm was a Protula, that some of its descendants, which had already become developed into perfect Protulae, subsequently improved themselves by the formation of an operculum which might protect their tubes from inimical intruders, and that subsequent descendants of these latter finally lost the lateral filaments of the opercular peduncle, which they, like their ancestors, had developed.

Fritz Muller - Facts and Arguments for Darwin