ON THE LOCOMOTOR SYSTEM OF ECHINODERMATA. 
885 
Fig. 16. Nerve-cells lying amongst muscular fibres at base of spine. 
Fig. 17. Nerve-fibres lying between epidermis and calcareous stem of pedicellaria. 
Fig. 1 8. Plexus lying over muscular fibres near base of mandibles of pedicellaria. 
Fig. 19. Natural co-ordinated movements of common Star-fish. 
Fig. 20. Natural righting movements of common Star-fish. 
Fig. 21. Natural righting movements of Astropecten. 
Fig. 22. Natural locomotor movements of Ophiura. 
Figs. 23-26. Natural righting movements of Echinus. 
Fig. 27. Righting movements of severed ray of common Star-fish after bisection of 
radial nerve. 
Fig. 28. The unco-ordinated movements of inverted Star-fish after section of the five 
radial nerves. 
Fig. 29. Tulip-shape assumed by the same. 
Figs. 30, 31. Righting movements of segments of Echinus. 
Figs. 32-34. Righting movements of Echinus on a vertical surface. 
