Body wall muscles in the haplotaxidsHaplotaxis gordioides andPelodrilus leruthi (Annelida,Oligochaeta)

Summary The muscle organization of the body wall in two species of Haplotaxida is described.Haplotaxis gordioides andPelodrilus leruthi show significant differences in the longitudinal muscle layer. The observations suggest that inH. gordioides, the muscle fibres could foreshadow the flat circomyarian organization of microdrile muscles, while theP. leruthi organization recalls the pinnate arrangement of megadrile body wall.