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Show 1899.] CRANIAL OSTEOLOGY OF THE PARROTS. 17 deep excavation behind the squamosal or zygomatic process which is so marked and exceptional a feature in this bird, but which we now discover to be a huge development of the tiny groove in Psittacus, and of our IHrd fossa in Corvus ; and we further see that the opposite or inner wall of this last fossa, which so deeply overlaps and overhangs the head and shaft of the quadrate, is precisely comparable to that little process Avhich did likewise, but to a slight degree, in the Grey Parrot and the Crow. Nestor meridionalis, for comparison with figs. 4 & 5. (Letters as in previous figures.) The tympanic cavity is of moderate size, widely open wmen we look at it from in front, but in its lateral aspect almost concealed by the forward growth of the scroll-like posterior wall; the cavity has a deep posterior recess, descending to near the apex of the paroccipital process, where is a large oval foramen for the so-called tensor tympani. The lower and anterior border of the meatus, as it bends upwards, quite distinctly shuts out the region of the quadrate articulation from the boundaries of the tympanic cavity. The quadrate bone (fig. 7) has two widely separate capitula, the Quadrate bone of Nestor meridionalis. (Letters as in previous figures.) inner one being in a considerable degree the smaller; but the double socket for these heads, though constricted in the middle, PROC. ZOOL. Soc-1899, No. II. 2 |
