Vertebral column composed of about 50 vertebrae, viz.
Hymenochirus is further remarkable for the presence of only six distinct pieces in the vertebral L C FIG.
The scapula is sabre-shaped, and extends backwards over the ribs, lying almost parallel to the vertebral column.
This is the most perfect arrangement attained by the vertebral column, and is typical of, and restricted to, birds.
Later those pads fuse with the anterior end of the centrum of the vertebra to which they belong; where the vertebral column is rendered inflexible, the disks are ossified with the centra and all trace of them is lost.