Role of the abdomen in the regulation of shell position in the hermit crabPagurus pollicarus

摘要: 1. The hermit crab,Pagurus pollicarus, carries its shell at a relatively constant position above the substrate; this is linear function of weight shell. Abdomen and right fifth pereiopod lift with abdomen providing about one-tenth total lift. 2. In restrained animals suspended, curvature to flexion vary as load; phasic mechanical stimulation increases generates lift. 3. Abdominal tone also influenced by fourth and, lesser extent, pereiopods. Positioning pereiopods forward abdominal tone, positioning them posteriorly decreases it. 4. Intra-abdominal maintenance seems be done an open loop central excitatory state rather than homeostatic control or tension.