50 TKsTUniMD.E. 



2. Alveolar surface of upper jaw without median ridgo. 



a. Choanie behind tho level of the eyes ; alveolar surface of 

 jaws very broad. 

 Inguinal buttress anchylosed to the fifth costal plate; upper surface 

 of head covered with undivided skin: eiilo])lnstron anterior to 

 the huinero-pectoral suture 8. Malacoclemmys, p. 88. 



Inguinal buttress anchvloscd between tlie fifth and sixth (excep- 

 tionally fourth and "fifth) costal plates; hinder part of head 

 covered with small sliields ; entoplastron intersected by the humero- 

 pectoral suture 0. Damonia, ]). i»2. 



6. Choanal between the eyes; entoplastron intersected by 

 the humero-pectoi'al suture. 



a. Plastron not hinged. 

 Axillary and inguinal buttresses strong, latter anchylosed between 

 the fifth and sixth costal plates ; hinder part of head covered 

 with small shields 1<». Bellia, p. 97. 



Axillary and inguinal buttresses short, latter just reaching the fifth 

 costal plate ; upper surface of head with undivided skin. 



11. Cleinmys, p. 100. 



/3. I'lasti'on hinged, movable. 



A bony temporal arch; beak not liooked. 



12. Emys, p. HI. 



No bony temporal arch ; beak hooked. 



i:5. Cistudo, p. lU. 



B. Hexagonal neural plates (at least the anterior) short-sided 

 behind ; entoplastron intersected by the humero-pectoral 

 suture. 



Plastron not hinged ; a bony temporal arcli. 



14. Nicoria, p. 118. 



Plastron hinged, movable ; a bony temporal arch. 



15. Cycleinys, p. 128. 



Plastron not hinged ; no bony temporal arch. 



16. Geoemyda, p. 135. 



II. Digits without a rudiment of web, with not more than two 

 phalanges ; metacarpals not or but slightly longer than broad ; 

 neural plates mostly hexagonal, short-sided behind, or alter- 

 nately tetragonal and octagonal. 



A. Alveolar surface of upper jaw without a median ridge. 



Posterior portion of carapace hinged, movable. 



17. Cinixys, p. 140. 



