Asterias, many times enlarged. The model shows in detail: 1. Complete arm with normal position of the organs (stomach, intestinal caeca, pyloric caeca, ampullae). 2. Arm with ampullae, ring canal, Polian vesicles. 3. Skeleton of the arm with nervous system (nervering and radial nerves). 4. Arm in transverse section (ambulacral system in cross-section). The cut surface shows the stomach, stone canal, axial organ and madreporite. In addition on the outside the podia, pedicellariae and optic organs are shown. Comprises 3 parts. On a removable stand and base.
