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Show 456 PROF. HUXLEY ON THE CLASSIFICATION OF BIRDS. [Apr. 1 1, It is unnecessary to enumerate the arguments by which the close affinity of the proper Passerine birds (which make up the great bulk of the iEgithognathous section) may be demonstrated, as the eminently natural character of this group is admitted by every one. In their cranial characters, the Swifts are far more closely allied with the Swallows than with any of the Desmognathous birds, the Swift presenting but a very slight modification of the true Passerine type exhibited by the Swallow. No distinction can be based upon the proportions of the regions of the fore limb ; since in all the Swallows which I have examined* the manus and the antebrachium, respectively, greatly exceed the humerus in length, though the excess is not so great as in Cypselus. The modification commenced in the Swift is greatly exaggerated in Algotheles and Caprimulgus; while we have almost a transition to the Desmognathous structure in Nyctibius. But if palatine characters have the taxonomic value which the facts just enumerated appear to indicate, it follows that the Dromceognathous structure, so different from what is to be seen in any other Carinate birds, has as much value as the rest, notwithstanding the small actual extent of the group in which it obtains. It thus appears that the Dromaeognathous, Schizognathous, Desmognathous, and iEgithognathous arrangements of the maxillary and palatine bones, respectively, characterize divisions of the Carinatae, all the members of which are mutually affined in other respects. And I propose to regard these divisions as suborders, and to name them D R O M ^ E O G N A T H ^ E , S C H I Z O G N A T H J E , DESMOGNATHiE, and iEGITHOGNATH^E-f. The suborder DROM^EOGNATH^E, containing only one family, the Tinamidee, admits of no subdivision into groups of larger extent than families; but the other three suborders are very extensive, and, I think, may be so subdivided in an approximately satisfactory manner, though any definition of these subdivisions which can be proposed at present must be regarded as provisional and open to extensive revision as our knowledge of the details of ornithic organization widens. The SCHIZOGNATH^E. In addition to their cranial characters, the birds composing this suborder often want intrinsic muscles in the lower larynx, and never possess more than one pair of them. With the exception of Podiceps, all the genera which have been examined have two carotid arteries. Six groups of allied families are distinguishable in this suborder. These may be termed the C H A R A D R I O M O R P H ^ E , the G E R A N O - M O R P H ^ E , the C E C O M O R P H . E , the SPHENISCOMORPH^J;, the A L E C TOROMORPHA, and the PERISTEROMORPHCE^. * Hirundo pacifica, H. riparia, H. rustica, H. urbica. t Dromceus, the generic name for the cassowaries; e^t'Sk", to cleave; deaftbs, a bond; AiyiOos, a sparrow. J XapaSpibs, a sea-lark, or plover; Tepavos, a crane; Krj£, a gull; Spheniscus, a genus of penguins; 'AXeKnop, a cock ,- Uepiartpci, a dove; juop0>}, form. |
