Functional morphology of the setal protractors in Pheretima posthuma (Vaillant).
D000818:Animals; D016782:Apicomplexa / Q000166:cytology / Q000502:physiology*; D008124:Locomotion; D009119:Muscle Contraction; D009132:Muscles / Q000166:cytology; D009469:Neuromuscular Junction / Q000166:cytology