The ribs are short imperfectly ossified structures, bifid at their proximal end where they articulate with the transverse processes, and tipped both proximally and distally with cartilage. The dorsal portion of the proximal end corresponds to the tuberculum of the ribs of higher animals, and the ventral portion to the capitulum. Some of the anterior ribs have a step-like notch on their dorsal surfaces.
The second to twelfth ribs are fairly equal in size, but further back they decrease slightly. The ribs which connect the sacral vertebrae with the ilia are however large. The short ribs borne on the anterior caudal vertebrae are cartilaginous.
D. The Sternum.
The sternum (fig. 22, A, 6) is a rather broad plate of cartilage, drawn out posteriorly into a median process marked by a prominent ridge. On its antero-lateral margins it bears surfaces for articulation with the pectoral girdle.
2. The Appendicular Skeleton.
A. The Pectoral girdle.
This is of a very simple character, and remains throughout life in an imperfectly ossified condition. It consists of a dorsal scapular portion, and a ventral coracoid portion partially divided into an anterior part, the precoracoid, and a posterior part, the coracoid.
Fig. 22. A ventral, and B lateral view of the shoulder girdle and sternum of an old male Crested Newt (Molge cristata) × 3 (after Parker).
| 1. scapula. | 4. glenoid cavity. |
| 2. suprascapula. | 5. precoracoid. |
| 3. coracoid. | 6. sternum. |