. Annual report. 1st-12th, 1867-1878. Geology. 8HUFELCT. OSTEOLOGY OF THE CATHAKTID^E. 749 condyle is fully as large as in our specimen of Aquila canadensis ; indeed, as a rule it seems to be larger throughout the Vultures thau in the Falcomdce. In Polyborus tharus it is completely sessile and hemispheroidal in form, being still smaller, and in the Crows and Jays we know it is com- paratively still more diminutive. The area that includes the foramen magnum and the occipital condyle, and is bounded laterally by the ele- vated aural ridges, is depressed below the surrounding points in the basi-c
. Annual report. 1st-12th, 1867-1878. Geology. 8HUFELCT. OSTEOLOGY OF THE CATHAKTID^E. 749 condyle is fully as large as in our specimen of Aquila canadensis ; indeed, as a rule it seems to be larger throughout the Vultures thau in the Falcomdce. In Polyborus tharus it is completely sessile and hemispheroidal in form, being still smaller, and in the Crows and Jays we know it is com- paratively still more diminutive. The area that includes the foramen magnum and the occipital condyle, and is bounded laterally by the ele- vated aural ridges, is depressed below the surrounding points in the basi-cranii of all of the Cathartidce. In this space on either side we dis- cover the usual venous and nervous foramina, the precoudyloid foramina, and those for the vagus and jugulars, the latter group occupying the base of a special depression for themselves. We find in many birds, beyond the condyle, on either side, a descend- ing tuberous process; they show pretty well in a fine specimen of the Canada Goose that we have at hand, while they are entirely absent in our skull of Circus, and only moderately developed among the Eagles. In the Cathartidce, however, this pair of processes become the leading feature of the base of the cranium, though it must be remarked that they are not always equally well developed, for we have crania of C. atrata in our possession in which one would hardly be struck by them as worthy of particular notice. In one of our skulls of 8. gryphus, however, and another of the Californian Vulture, these processes are remarkably well developed, being great tuberous projections that spring from ex- tensive bases, taking a direction down wards, outwards, and a little back- wards. Their inferior extremities seem to be designed for muscular and ligamentous attachment. In the accompanying cut, Sp designates this pair of processes, and Tp a quadrate bone. This fig- ure is life-size from the smaller skull of the two specimens we have of our Californian Vulture; it illu
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