EXPLANATION OF PLATE VL 



Figs. 1-4. Agathaumas sylventre, one-fourth natural size. 



Fig. 1. A ? rib. 



Figs. 2-3. Undetermined bone8. 



Fig. 4. Neural arcb of a donsal vertebra minus the processes. 



Figs. 5-8. Bottoaauriis perrugosus, one-half natural size. 



Fig. 5. A posterior dorsal vertebra from front : a, from behind, and, h, from below. 



6. Posterior part of mandibular ramus from outer side ; 6, from inner side. 



7. Portion of deutary bone with alveoli : a, from inner side ; 6, from outer side. 



8. Distal end of femur found with the preceding ; a, lateral view. 



Figs. 9-16. Fragments of tortoises from the Cretaceous of Colorado, natural size. 

 Fig. 9. PlaKtonuiiHs pnnctidatus, costaXhone, 



10. P. insiijnis, liyposternal bone. 

 Figs. 11-12. Adocus liueolatus : 11, from plastron ; 12, vertebral bone. 

 13-14. Triouijx ragaiis, portious of costal bones. 

 15-16. Marginal bones of Compsemys victua. 



