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Show 1905.] OSTEOLOGY OF THE E U R Y L ^M ID ^ . 39 corresponding to the sub-crescentic plates of Calyptomena. These hemipterygoids, in both the Eurylsemid and Cotingid forms, articulate with the palatines, in the adult, by means of an oblique suture. Corydon, and Cymbirhynchus differ in no essential features from Calyptomena. 1 he quadrate is peculiar in that, in common with the Tyrannidse and some other Passerine forms, it sends out a strong spur for the articulation of the quadrato-jugal bar. This spur projects like a buttress laterad of the outer condyle for the lower jaw. The squamosal and otic heads are closely approximated. The former is wedged in between a prominent processus articularis squamosi behind, and an e.qually well-developed processus articularis zy<jo-maticus in front. In Corydon these processes are expanded laterally so as to overhang the head of the quadrate, but at the same time they afford this element a greater freedom of movement than in Calyptomena. Cymbirhynchus and Eurylcemus are intermediate in character in this respect. The Mandible. The mandible, in the Eurylaemidse, is much bowed outwards to a very considerable extent. In Calyptomena it has only a relatively small symphysis: is truncated posteriorly, and shows little or no trace of the separate elements of which it is composed. The internal angular process is moderately well developed, and is perforated by a small pneumatic foramen. The rami, in their general shape, are rod-like, and slightly compressed laterally. In Corydon and Cymbirhynchus, however, there is an abrupt transition between the malar region of the mandible and that portion covered by the rhamphotheca, which is most markedly thicker and broader than the hinder region. The sympbysial region is very broad and spoon-shaped. The internal angular process is more spine-like than in Calyptomena, and there is a feebly-developed posterior angular process. The Hyoid. The hyoid of the Eurylaemidse resembles that of the higher Passeres. The basiliyal (os entoglossum) is made up of a pair of boomerang-shaped ossifications placed dos d dos, so that a long free process is produced backward beyond the articulation with the basibranchial 1. Basibranchials 1-2 are fused; the latter, however, is a long cartilaginous style. The ceratobranchial and epibranchials are of moderate length ; the latter are cartilaginous at the free ends. In Corvus, for example, among the higher Passeres, the basi-hyals are long and straight, and run parallel with one another, yet so as to leave a median space between them. |