Postural control of shell position by the abdomen of the hermit crab, Pagurus pollicarus. III. Analysis of movements and calculations of forces exerted by the muscles

摘要: Experiments with a transparent plastic snail shell indicated that the hermit crab carries columella in crook of its bent abdomen. There are three components to normal curvature abdomen region third segment, ventroflexion 30°, pitch right 10°, and clockwise rotation 20° whole about thoracic-abdominal junction. The forces bending moments produced by ventral superficial muscles were estimated from sizes muscles, their position on circumference abdomen, amplitudes EJPs motoneurons, firing frequency. These calculations reasonable agreement behavioral measurements.