Pare 25. 
de 
e t8 
. Skull of Chelone convexa, side view. 
2. Ditto base view. 
3. Ditto top view. 
4. Base view of part of skull of Chelone trigoniceps. 
5. Under view of symphysis of lower jaw of ditto. 
6. Upper view of the same specimen. 
7. Back view of ditto. 
11. Side view of ditto. 
8. Part of symphysis of the lower jaw of the Chelone acuticeps. 
10. Side view of ditto. 
9. Upper view of the symphysis of the lower jaw of the Chelone longiceps. 
12, Side view of a sacral vertebra of a fossil Trionyæ. 
13. Side view of a corresponding vertebra of a recent Trionyæ. 
14. Front view of the same fossil vertebra. 
15. Front view of the same recent vertebra. 
16. Top view of the same fossil vertebra. 
17. Top view of the same recent vertebra. 
18. Flattened symphysis of the lower jaw of the Chelone acuticeps. 
e RS 
