. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. AVES. 275 the cerebrum are lodged, the rest of the brain is contained in the posterior division. The relative proportion of these divisions varies in the different orders; in the Insessores and Ac- cipitres the anterior superior depression is the largest; in the Rasorcs, the posterior inferior depression equals, and in some species, ex- ceeds the former in size. The orbits form two slight projections in the anterior fossa of the cranium, which is partially divided longitu- dinally by a ridge corresponding to the inter- s
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. AVES. 275 the cerebrum are lodged, the rest of the brain is contained in the posterior division. The relative proportion of these divisions varies in the different orders; in the Insessores and Ac- cipitres the anterior superior depression is the largest; in the Rasorcs, the posterior inferior depression equals, and in some species, ex- ceeds the former in size. The orbits form two slight projections in the anterior fossa of the cranium, which is partially divided longitu- dinally by a ridge corresponding to the inter- space of the cerebral hemispheres. This is developed in the Gallinaceous birds into a thin falciform osseous crest, which is especi- ally remarkable in the Partridge, Turkey, and Capercailzie. It is also well developed in the Parrot tribe. The sclla turclca in all birds is a deep round cell, lodging the pituitary gland, as in the Mammalia. The foramen magnum (\ ,fg. 126) is formed, as usual, by the union of the four pieces of the occipital bone : its size is considerable, having relation to the mobility of the cranium upon the spine. The foramen lacerum posterius (2, 2, Jig. 126) is situated immediately below the membrana tympani (8, 8,fg. 126.) There is no fissure analogous to the foramen lacerum medius. The carotid foramina (3, 3, Jig. 126) are transversely oblong, and situated on the body of the sphenoid; the same bone, in the Ostrich, is perforated immediately anterior to the carotid canal by the Eustachian tube, (4, 4.) The posterior palatine foramina are wide spaces, (5, 5,) separated from each other by the vomer ((h f'S- 126). Anterior to these, in the base of the skull, are seen the still wider posterior apertures of the nostrils (6, 6). In the inside of the cranium the internal auditory foramina are distinctly seen. The foramen lacerum an- terius is divided into several distinct foramina. The optic foramina, on the contrary, are closely approximated, and frequently ble
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