OCR Text |
Show 1867.] PROF. HUXLEY ON THE CLASSIFICATION OF BIRDS. 423 2. The maxillo-palatines are flat, imperforate plates, which unite solidly with the praemaxillae and the vomer. 3. The vomer is long, and articulates behind with the palatine and pterygoid bones. 4. The prefrontal processes are large and well ossified. 5. The bodies of the proper sacral vertebrae do not unite with the pubes or ischia ; and the bodies of the urosacral vertebrae are very large, thick, and well ossified. 6. The sternum is long and escutcheon-shaped, at first widening and then coming to a point behind. 7. The humerus is not nearly half so long as the distance between the pectoral arch and the ilium, and is much shorter than the scapula. The antebrachium is not more than half as long as the humerus. Only one digit, the median, is complete and bears a claw. 8. Neither the pubes nor the ischia unite in the middle line of the body. 9. The hallux is absent, but the other digits are complete. 10. There are thirty-five precaudal vertebrae. 11. The feathers have aftershafts as long m the principal shafts. The extinct Dinornis of New Zealand differs from the other Ratitae, and thus represents a fourth group, in exhibiting:- 1. A skull with high arched beak and projecting occipital condyle. 2. Flat, imperforate maxillo-palatine plates, which unite solidly with the praemaxillae and probably with the vomer, as in Dromceus. 3. A Dromaeine pelvis. 4. A broad sternum with two posterior notches. 5. A very rudimentary pectoral arch, which appears to have possessed no glenoidal cavity for the articulation of the humerus. 6. Three toes, the hallux being absent. 7. The feathers have an aftershaft*. Lastly, the remarkable living New Zealand genus Apteryx represents a fifth division, having:- 1. The palatines short and broad, and uniting by an oblique suture with the expanded maxillo-palatines, which are flat, imperforate plates uniting with the premaxillaries and the vomer. 2. The vomer long and uniting with the palatines and pterygoids posteriorly. 3. The prefrontal processes very large and spongy. 4. The bodies of the proper sacral vertebrae not united with the ischia or pubes ; the urosacrals large and well ossified. 5. The sternum broad and with two posterior excavations. 6. The humerus longer than the scapula, and extending for about half the distance between the pectoral arch and the ilium. The antebrachium about half the length of the humerus, and the manus possessing but one claw. 7. Neither the pubes nor the ischia united in the middle line of * See Dallas, Proceedings of the Zoological Society, 1865. |