PLATE XXI. 



1. Distal convex face of the " article basal," the top joint. 



2. Proximal face of same. 



3. Young joint or anehylosed infrabasals? resting upon the convex face of the " article basal " (Fig. 1, 



on the central part). 



4. Reticulation of central part of proximal surface of basal joint. 



5. One segment of a young stem joint with sixteen lobes, lying between the eighth and ninth joints. 



6. Sixth stem joint, distal face, with fourteen irregular primary ridges and numerous minor peripheric 



ones. 



7. The proximal face of the same, having sixteen primary sockets. 



8. 9. The distal and proximal faces of the ninth joint, with sixteen primary ridges bifurcating near 



the edge and their corresponding sockets on the opposite face. 



