EXPLANATION OF PLATE XII. 



Bones of Proiostega gigas, one- third natural size, except Fig. 1, which is oue-half nature. 



Fig. 1. Neural arch of ? cervical vertebra, from above. 



2. Left humerus. 

 Figs. 3-4. Metapodial bones. 

 Fig. 5. Seapulo-procoracoid of the right side. 



6. Coracoid of the right side. 

 Figs. 7-9. Phalanges. 

 Fig. 10. Normal lateral marginal bone, from below. 



11. Vertebral ? nuchal bone, from above. 



12. Marginal bone with two lamina}: a, from without ; b, from the proximal or inner margin. 



13. Long anterior marginal bone. 



