The Vertebrate Skeleton

by Sidney H. Reynolds

Æpyornithes[98], huge extinct birds from Madagascar.

Apteryges, including the Apteryx of New Zealand.

Dinornithes[99], the Moas, huge extinct birds from New Zealand, and some of the neighbouring islands.

Megistanes, including the Cassowaries (Casuarius) of Australia, New Guinea, and some of the neighbouring islands; and the Emeus (Dromaeus) of Australia.

Rheornithes, including the Rheas of S. America.

Struthiornithes, including the Ostriches (Struthio) now living in Africa, and found fossil in N. India and Samos.

Order 2. Odontolcae.

This order includes only an extinct N. American bird Hesperornis[100]. The jaws are provided with a series of sharp teeth placed in continuous grooves, but the premaxillae are toothless, and were probably sheathed in a horny beak. The rami of the mandible are not ankylosed together in front. The skeleton is not pneumatic. The cervical vertebrae have saddle-shaped articulating surfaces as in ordinary birds, and the thoracic vertebrae are not ankylosed together. The tail is comparatively long, and formed of twelve vertebrae with only slight indications of a pygostyle. The ribs have uncinate processes. The anterior limb is quite vestigial, being reduced to a slender humerus. The posterior limb is very powerful and adapted for swimming.

Order 3. Carinatae.

This order includes the vast majority of living birds. The cervical vertebrae have saddle-shaped articulating surfaces (except in the Ichthyornithiformes). The posterior caudal vertebrae are ankylosed forming a pygostyle. The quadrate articulates with the cranium by a double head. In all except the Tinamidae the vomers are narrow behind and not interposed between the palatines, pterygoids and basisphenoidal rostrum. The sternum has a median keel, and the anterior limbs are in the great majority of cases adapted for flight. Clavicles are well developed, and the scapula and coracoid are nearly at right angles to one another. The various groups into which the Carinatae are divisible are shown in the table on pp. 40-42. Their special characters will not be dealt with.