EXPLANATION OF PLATE XL 



Bones of the same specimen of Protostega gigas. 



Fig. 1. Pterygoid and columellar plate of left side. 



2. ? ADterior part of pterygoid. 



3. Postfrontal bone : a, from inside ; b, from outside. 



4. Vertebral centrum flattened by pressure: a, from above ; h, from below. 



5. ? Cervical vertebra: a, centrum (flattened) from below; b, from side; c, neural arch from side; 



d, from above. 



