Regeneration of the penis in Balanus balanoides (L.)

In Balanus balanoides (L.) the penis is ‘lost’ each autumn. The regeneration of the penis is described. The primordium contains mesenchyme. The pedicel structures develop early as thickened areas of the exoskeleton and give rise to the characteristic structural features of the mature pedicel. Tissue differentiation begins in the pedicel and later extends to the penis proper which becomes annulated. The ductus eventually opens by a terminal invagination of the exoskeleton.