43 



Fig. 9. Abaxial face of a first primibracliial. x 8. 



Fig. 10. Lateral face of a second primibracliial axil- 

 lary). X 8. 



Fig. 11. Ural face of a second primibracliial. x 8. 



Fig. 12. Proximal face of a first secundibrachial. x 8. 



Fig. 13. Proximal face of a secundibrachial joint from 

 tbe base of an arm. x 8. 



Fig. 14. Distal face of a secundibrachial joint from the 

 base of an arm. x 8. 



Fig. 15. Distal face of a secundibrachial joint from near 

 the tip of an arm. x 8. 



Fig. IG. Distal face of the hypozygal joint of the first 

 syzygial jiair. x 8. 



Fig. IT. llosette plate, from the oral surface. x 12. 



Fig. 18. Lateral view of rosette plate. x 12. 



Fig. 19. Oral face of ceutro-dorsal plate showing its 

 cavity. x 10. 



Fig. 20. Half of aboral face of centro-dorsal plate, 

 showing the sockets for the articulation of the 

 cirri. x 10. 



Fig. 21. Side view of four secundibrachial joints from 

 the base of an arm, with the proximal joints of 

 two pinnules in situ. The soft parts had been 

 removed by maceration in caustic potash 

 solution. X G. 



Plate II. 



Fig. 22. Portion of a vertical section of the tegmen 

 calycis, showing two ciliated funnels. x 320. 



Fig. 23. Oral face of the disc, with the alimentary canal, 

 reconstructed from serial sections, seen by 

 transparency. x G. Adapted from L. Cuenot. 



Fig. 24. Oral face of the disc and the bases of the arms 

 of Antedon bifida. x G. 



