THE GEOGRAPHIC TURTLES. 83 



PLATE II. 



EXPLANATION OF THE FIGURES. 



FIG. 1. Outline showing slope of carapace in young 31. lesueuri. 



FIG. 2. Same of young M. yeoyraphicus. 



FIG. 3. Same of adult M. lesueuri. 



FIG. 4. Same of adult M. yeoyraphicus. 



FIG. 5. Ventral side of skull of M. yeoyraphicus; mx, maxilla; v, 

 vomer; pi, palatine bone. 



FIG. 6. Ventral side of skull of M. lesueuri with same bones out- 

 lined. 



FIG. 7. Ventral side of skull of Pseudemys elegans, for comparison 

 with Figs. 5 and 6. 



FIG.. 8. Right side of skull of M. lesueuri, dorsal view ; mx, max- 

 illa ; ns, naso-prefrontal ; fr, frontal ; pfr, post-frontal ; p, 

 parietal. 



FIG. 9. Same of M. geoyraphicus, showing difference, especially be- 

 tween the frontal bones. 



FIG. 10. Itight ramus of mandible of an adult M. yeoyraphicus. 



Fig. 11. Same of an adult M. lesueuri. 



NOTE. The observations of which the above is the result were 

 made at odd times while connected with the Illinois State Laboratory 

 of Natural History and are based chiefly on material collected by the 

 writer in the Mississippi and Ohio rivers and their Illinois tributa- 

 ries, but partly also on specimens collected or examined elsewhere in 

 the United States. 



