AA. Cartilage Bones, Endoskeletal
1. Notochordal vertebrae; two or three cervicals, about twenty-three presacral; one sacral; moderately long tail; proatlas; atlas embolomerous; all vertebrae to tenth or twelfth caudal with free, holocephalous ribs, articulating continuously with intercentrum and diapophysis.
2. Intercentra between all vertebrae.
3. Slender and numerous parasternal ribs.
4. Scapular girdle composed of paired scapulae, procoracoids and metacoracoids, fused in adult life, the three forming the glenoid socket; a supracoracoid and a supraglenoid foramen.
5. No sternum.[1]
6. Pelvis plate-like with small obturator foramen only; acetabulum formed by the three bones, closed.
7. Legs short and stout.
8. Humerus dilated at extremities, with entepicondylar foramen.
9. Carpus with four bones in proximal row; two (three?) in middle row; five in distal row; all well ossified.
10. Hand pentadactylate, the fourth finger strongest and longest; phalangeal formula 2, 3, 4, 5, 3.
11. Tarsus composed of nine bones: two in first row[2]; two in second; five in distal row; all well ossified.
12. Feet pentadactylate, the fourth toe strongest and longest; phalangeal formula 2, 3, 4, 5, 4.
