Plate v. • 



Pourtalesia Jeffreysi Wyv. Thoms. 



The ambulacral system coloured. 



Fig. 25. The calycinal system and the surrounding area, p. 79. 



Fig. 26. The same from the inside. 



Fig. 27. The calycinal system and surrounding area, in another specimen. 



Fig. 28. The same from the inside. 



Fig. 29. The termination of the front ambulaorum. 



Fig. 30. The articulating end of a spine, p. 24. 



Fig. 31. The corresponding tubercle. 



Fig. 32. The lower end of a spine. 



Fig. 33. A calcareous fibre rising from the coUar. 



Fig. 34. A fibre with its processes, side view. 



Fig. 35. Another fibre, front view. 



Fig. 36. An oar-like spine; shortened. 



