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Show 1899.] CRANIAL OSTEOLOGY OF THE PARROTS. 41 in a greater or less degree, the two areas become connected, with less or more interruption, by a definite ridge. N o w in the Parrots the inner or sub-pterygoid condyle becomes so extremely enlarged and so elongated from before backwards, that at first sight it appears to form the entire articulation. With its antero-posterior extension it has also undergone a downward expansion, while the region of the bone below the jugal cup is not only thereby raised far above the level of the inner (or true) condyle, but at the same time becomes much less prominent in the outward or lateral direction. This is oue of the respects in which. Stringops seems to have undergone less modification than the others, for the region bearing the jugal cup is very prominent laterally and less raised than in the others above the level of the main condyle. W e have seen that more or less in all Parrots the edge of the mandible plays upon the side of the quadrate below the jugal cup, and we now recognize that this is not a new and fortuitous contact, but a more or less obsolete survival of what in Birds in general is one-half of the primitive articulation. In the Cockatoos, especially in Microglossa, and in the Macaws, this articular facet below the jugal cup is quite distinct, and in Stringops it is also well-marked and points downwards ; in Microglossa, where the jugal region of the quadrate is also prominent, though less so, it likewise looks more or less downwards, while in the Macaws and others it lies on a more nearly vertical slope. It is more difficult to determine how or to what extent the posterior extension of this outer condyle, that we have seen to be so well-marked in many birds, is represented in the Parrots. W e might be inclined to imagine, from the manner in which it sometimes comes, as I have described above, to approximate with the inner condyle, that the large size of the latter in the Parrots was due to a fusion of the two ; but the absence of any change in the relations of the corresponding cavity in the mandible forbids m e to think so. I take it that this portion of the quadrate is still represented by that region of the bone immediately behind the pterygoid cup which, reduced or truncated in most Parrots, is comparatively prominent in Stringops. And although this area no longer serves an articular purpose, I think we may recognize it (both in its more highly developed form in Stringops. and in the shape of a smaller tubercle in Ara and Microglossa and of an elevated protuberance in Conurus &c.) by its relations to the quadrato-jugal cup, behind which it lies, and to the region bearing the main condyle which curves evenly backwards towards it. I have already shown that in its complete orbit, formed by a junction of the prefrontal and postfrontal elements, Stringops is unique among the Old-World Parrots ; its temporal fossa is disproportionately large compared with all the rest; the grooved surface posterior to the squamoso-temporal articulation and overhung by the suprameatal process is by far more developed than in any other Parrot except Nestor, though in this respect Stringops itself is far from approaching that peculiar type, and such resemblance as this |