EXPLANATION OF PLATE XXVII. 



Fig. 1. One cervical and five dorsal vertebra), with a rib, of Platccarpus latispinus, iu place, one-half 

 natural size ; from Professor Sludge's collection ; profile. 



2. Last cervical and first dorsal, from below. 



3. Last cervical vertebra from front. 



4. Sixth dorsal : a, from front ; b, from below. 



5-10. Platecarpus tectulus, specimen from Professor Mndge's collection from near Sheridan, one-half 

 natural size. 



5. Median cervical vertebra from front. 



6. Median dorsal vertebra : a, centrum, from above; 6, from front. 



7. Atlas neurapophysis, from within. 



8. Quadrate bone : a, from outside ; l>, from inside ; c, proximal end ol fragment. 



9. Frontal bone, fragment, from above. 



10. Parts of angular and articular bones with cotylus of mandible. 



11. Third cervical vertebra of Liodon dyspclor, the Fort Wallace specimen, from behind, one-half 



natural size. 



