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Show 1877.] ANATOMY OF PASSERINE BIRDS. 451 almost every order-in Rhea and the Megapodes among the Galli-formes, in Arctica aile and Turnix among the Charadriiformes, in Sula fusca and Plotus anhinga among the Ciconiiformes, &c. The disappearance here and there of the ambiens muscle and of the femoro-caudal, as well as of the colic cseca, all come under the same category, as simple operations which lose their significance in the determination of affinity in proportion to the frequency of their appearance, or to the facility with which they are induced, as I would assume. The figure of the superior surface of the skull of Furnarius rufus (p. 450), when compared with those of Charadriiform birds in my paper above quoted1, will show the resemblance between the two, as far as the point under discussion is concerned. In questions of doubtful affinity among the birds under consideration, this character proves to be of service. For example, the genus Margaronis is differently placed by leading ornithologists-by some along with the Sclerurinse on account of the shortness of its outer toe, by others with the Dendrocolaptinse because of the stiffness of its tail-feathers. From the skull, an example of which I have had the opportunity of removing from a skin of Megarornis perlata, through the kindness of Mr. Salvin, I feel no doubt that it is not Dendrocolaptine, because the nasal bones agree exactly with those of Furnarius rufus and the other schizorhinal Passeres above mentioned. I may also mention that in these schizorhinal tracheophone Passeres, as also in their allies the Pteroptochidae, the maxillo-pala- Fig. 4. Palatal view of skull of Pteroptochus albicollis. tine plates of the maxillary bones, instead of terminating by blunt uncurved tips, as in the non-oscine (mesomyodian2) Passeres generally, including Dendrocolaptes, Thamnophilus, and their nearest allies, are slender and curved backwards as in the Oscines. A study of the superb plates in Mr. Parker's Memoir on ^Igithognathous Birds3 will illustrate this point, which an inspection of other skulls 1 P.Z.S. 1873, p. 34. 2 P.Z.S. 1876 3 Trans. Zool. Soc. vol. ix. p. 289, pl. lvi. figs. 8-10, lvu. figs. 8-10, et hx. |