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Show 1868.] PROF. H U X L E Y ON T H E A L E C T O R O . M O R P H A E . 309 Fig. 12. The right tarso-metatarsus of Opisthocomus, viewed from in front, the side, and behind, with the proximal and distal ends. The basal phalanx of the hallux is slender, curved, and considerably longer than that of the middle digit, as in the Pigeons. In Corythaix the two are equal in length. In the skull, the strong rostrum, united with the frontal region by a well-marked transverse hinge (figs. 13, 14, p. 310), and the forward extension of the nasal bones, narrowing the nasal apertures, gives the cranium a superficial resemblance to that of the Musophagidee. Closer examination, however, shows that the two are extremely different. In Corythaix the hinge lies, as usual, in front of the lachrymal bones, which are connected by sutural union altogether with the frontals, and the rostrum is formed by the praemaxillae and nasals. But in Opisthocomus the hinge lies behind the lachrymals, which have completely coalesced with the nasals and form an integral part of the rostrum. In Tetrao urogallus and in Crax, the inner margins of the lachrymals are connected almost wholly with the nasals, and their posterior margins -are truncated and unite with the frontals only by a short, more or less transverse, suture. If the sutures between the nasals and praemaxillae, on the one hand, and the frontals, on the other, were as open as this is, the rostrum would have a hinge just like that of Opisthocomus ; and ankylosis of the lachrymals with the nasals would complete the resemblance. The mandible of Corythaix bears a good deal of general resemblance to that of a Pigeon. In Opisthocomus, the mandible is like that of Didunculus in general form, and has the peculiar flanging out of the upper margins of the rami, which is absent in Corythaix, but is so characteristic of the mandible in most Pigeons. The palatine bones (fig. 16, p. 311) have much resemblance to |