EXPLANATION OF PLATE III. 



Figs. 1-4. Polyonax mortuarius, oue-balf natural size. 



Fig. 1. Fragment of femur from side : a, same from below ; J, from above. 



2. Fragment of ? iscbium from side ; a, narrower extremity ; 6, stouter extremity. 



3. Broken fragment of the other ? iscbium, edge view, sbowing iulernal cavity. 



4. Inside view of part of fibula : a, superior end view of tbe same. 

 Figs. 5-6. Bones of Madrosaurus t occidentalis, from Colorado. 



Fig. 5. Fourtb sacral vertebra from tbe tide, one-balf natural size : a, same from below ; t, from front. 

 G. Fragment of bead of libia seen from above, four-tentbs natural size. 



