Chelonia
Chelonian shell is unique and very distinctive.
- Carapace (=upper shell)
- Composed of ~55-60 dermal bones
- Neural series fused to the vertebrae
- Costal series fused to the ribs
- Plastron (=lower shell)
- Composed of 9 bones
- Entoplastron is derived from interclavicle
- Epiplastra are derived from clavicles
- Bones of carapace and plastron covered by horny, epidermal scutes