TAB. II. 

 Chelone breviceps, four fifths of the natural size. 



Fig. 



1 . Upper view of the carapace. 



c/t. The nuchal plate. 



SI — s\o. The neural plates, most of which are connate with the neural spines. 



ph — -j)l8. The costal plates, connate with the pleurapophyses or vertebral ribs. 



in — V4. Impressions of the vertebral scutes. 



mi. The first marginal plate. 



2. Under view of the plastron and bent-down skull. 



PS. Episternal element of plastron. 

 M. Hyosternals. 

 ps. Hyposternals. 

 xs. Xiphisternals. 



3. Side view of skull. 



7. Parietal. 



8. Mastoid. 



11. Frontal. 



12. Postfrontal. 

 21. Maxillary. 



26. Malar. 



27. Squamosal. 



28. Tympanic. 



4. Outline of the transverse section of the middle of the thoracic-abdominal case. 



