EXPLANATION OF PLATE LIII. 



Fig. 1. Vertebral column, with pectoral fin, and impression of operciila of Empo sfmiaiiceps, Cope, one- 

 half natural size ; an interruption between the dorsal and caudal series is not filled by the 

 specimens : 1 a, obverse of the piece containing last dorsals, showing dermal bones. 

 2. Opercular, hyoraandibular, quadrate, and angular bones of another specimen o{ Enipo scviianctps 

 one-half natural size. 



Figs. 3-.5. Parts of a single specimen oi Empo nrpwolica. 



Fig. 3. Tho mandiliular ramus, natural size, from the inner side ; 3 a, the same, from the outer side ; 

 3 b, the angle and cotj'Ius, iiom behiud. 



4. Premaxillo-niaxillary bone of the same, natural size, viewed from below. 



5. Cervical vertebrai and basioccipital bone of the same, from below, one-half natural size. 

 Figs. 6-9. Portions of a skeleton of Empo scmianceps, natural size. 



Fig. 0. Dentary bone, from the outside. 



7. ? Pharyngeal bone, with dental alveoli. 



9. Dermal scuta. 

 Figs. 10-13. Empo merriUii, Cope, natural size. 



11-12. Premaxillary bone, from below. 

 Fig. 12. Proximal end. 



13. Pharyngeal bone, with alveoli. 

 Figs. 14-17. Empo conlrucla, Cope, natural size. 

 Fig. 14. Pharyngeal bone, with alveoli. 



15. Premaxillary and maxillary bones, from below. 



16. Proximal side of premaxillary, from the side. 



17. Dentary bone, from outer side. 



