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Show 1876.] OF /EGITHOGNATHOUS BIRDS. 257 liarities of the skull that belong to certain groups of families, which will, when once understood, be very helpful to Taxonomists. These more minute researches go to modify some of Professor Huxley's views, as expressed in his paper ' On the Classification of Birds' (P. Z. S. 1867, p. 415). Certain it is that the skull of a bird often seems to harmonize very ill with the rest of its structure, even with the rest of the skeleton. Still the morphology of this chief part of the framework, modified as it is in relation to the nervous, digestive, and respiratory systems, must be of the utmost importance to any one seeking to have broad views on these subjects. "The groups formed by cranio-facial characters have a variable value ; the desmognathous face passes over the Struthious border and is possessed by the gallo-struthious Tinamous. The saurognathous face (see Trans. Linn. Soc. 1875, plates i.-v.) is possessed by the " Celeomorphse " only-namely, by the Woodpeckers and Wrynecks. " The eegithognathous face is possessed by all the ' Coraco-morphse,' and by them only, in a perfect form, with the single exception of the Swifts (Cypselidae)-a mere big ** genus ' capable of being cut up into a few subgenera. " The desmognathous face turns up in many places ; its fundamental or embryonic form is the schizognathous, the simple reptilian cleft palate; this becomes desmognathous by ankylosis of the right and left elements of the palate. Desmognathism is seen in the iEgithognathse when ossification is very intense, as in Artamus, Paradisea, and Gymnorhina. " The simple, open, or cleft palate generally occurs in the groups that lie on a level two or three degrees above the Ratitse, as Rails, Plovers, Cranes, and the Fowl tribe; but it is also retained in types that in other respects are amongst the highest and most specialized, as the Trochilidse and the Caprimulgidee. " In the present paper research has been made into the morphology of the skull in the following groups-namely Tanagridse, Brachypodidae, Phytotomidae, Meliphagidee, Mniotiltidae, Ccerebidse, Vireonidae, Cardinalis, Icteridae, Emberizidse, Fringillidse, Alaudidae, Paridae, Panuridse, Cypselidae, Hirundinidse, Oriolidee, Motacillidse, Muscicapidse, Liotrichidae, Saxicola, and Nectariniidae. " And, lastly, the remarkable skull of Thinocorus is described, a small Chilian type, whose body is thoroughly Charadrian, but whose head is a mysterious mixture. Being imperfectly eegithognathous, it is here compared with the completely segithognathous Passerine types on the one hand, and on the other with birds much nearer akin, namely the Crane and the Sun-bittern. These latter, in an appendix, serve to compare with Thinocorus, and also show the schizognathous palate for comparison with the more complex palate of a Passerine bird. " Thinocorus, whilst essentially a Plover, if the characters of the skeleton generally be considered, yet shows more likeness in its skull to that variety of the Plover type which we see in the larger Cranes. PROC. ZOOL. Soc-1876, No. XVII. 17 |
