CHELONII. 



have considered the concavity of the sternum as a mark of the 

 male sex ; but this concavity is only found in the land tor- 

 toises, and cannot therefore be used for the purpose which 

 Sir E. Home supposes, (see Phil. Trans.) Mr. Sowerby 

 [Zool. Jour.) observes that a specimen in which this cha- 

 racter was distinctly marked, proved, on dissection, to be a 

 gravid female. Dr. Harlan appears to consider the length 

 of the tail as a character for this purpose, but I have not had 

 the opportunity of verifying his remark, which is not very 

 definite. 



Synopsis Familiarum et Genenim. 



Fam. I. TESTUDiNiDiE. — Pedes clavati, ungues 5-4 obtusi, 

 scutella caudalia unita. 



1. Testiido. — Testa dorsahs sternique solida. scutella 

 sterni 12. 



2. Chersina. — Testa dorsalis sternique solida, scutella 

 sterni 11. 



3. Kinyxis. — Testa dorsalis postice mobilis. scutella 

 sterni 12. 



4. Pyxis. — Sternum antice mobile. 



Fam. 11. Emyd^. — Pedes palmati, ungues 5-4 acuti, 

 scutella sterni 11 vel 12, 



5. Cistuda — Sternum latum cum testa symphysi carti- 

 laginea connexum, scutella sterni 12. 



6. Emijs — Sternum latum cum testa symphysi ossea 

 connexum, scutella sterni 12. 



7. KinosLernon. — Sternum latum cum testa symphysi 

 ossea connexum, scutella sterni 12. 



8. Chelydra. — Sternum angustum cruciforme. 



Fam. HI. Chelyd^. — Pedes palmati, ungues 5-4 acuti, 

 scutella sterni 13. 



9. Sternotheriis. — Maxillse corneee, sternum antice mobile. 



10. Chelndina. — Maxillae cornese, sternum solidum, scu- 

 tellum intergulare inclusum. 



11. Hydraspis. — Maxillse cornese, sternum solidum, scu- 

 tellum intergulare marginale. 



12. Chelys. — MaxiUae labiis carnosis tectse. 



Fam. IV. Trionycid^. — Pedes palmati, ungues 3-3 acuti, 

 testa cute molli tecta. 



