EXPLANATION OF PLATE LIV. 



Figures natural size, except (ig. 0, wliicU is tliree-fourtbs nature. 



Fig. 1. Preniaxillary and part of maxillary bones of TellKodim prpki-edo, Cope, natural .size, from the outor 

 Bide ; a, same, from inner side; 6, same, from lower side. 



2. Distal end of left dentary bone of the same, outer side, in natural relation with fig. 1. 



3. Distal eud of right dentary, from outer side; a, from above. 



4. Left premaxillary and part of maxillary bone of Enchodus pctromigj Cope, from the inner side; a, 



same, from outer side. 



5. Distal end of left dentary, from inner side, iu relation with tig. 4 ; o, the same, from above. 



6. Base of posterior partf of crauium of the same: a, basiiiccipital ; h, exoccipital; c, opisthotic; 



d, pterotic. 



7. Premaxillary and part of maxillary bone of Enclwdua duVuhiis, Cope, from outer side; a, same, 



from below. 



8. Scapula of Pelecopteriis chirurgus, exhibiting the facets for articulation of the two large and six 



slender basilar bones. 



