OCR Text |
Show 1867.] PROF. HUXLEY ON THE CLASSIFICATION OF BIRDS. 425 2. The long axes of the adjacent parts of the scapula and coracoid make an acute or a slightly obtuse angle, and are never, even approximately, identical or parallel*. The scapula always has a distinct acromion and the coracoid a clavicular process. 3. The vomer is comparatively small, and allows the pterygoids and palatines to articulate directly with the basisphenoidal rostrum*t*. In this order the bones which enter into the formation of the palate are disposed in four different modes, which may be called respectively the Dromceognathous, Schizognathous, Desmognathous, and AUgithognathous arrangement. I. The Dromceognathous Birds are represented by the single genus Tinamus, which (as Mr. Parker has shown J) has a completely stru- Under view of the skull of Tinamus robustus. From a specimen belonging to W . K. Parker, Esq., F.R.S. The letters as before, except * the prefrontal, and + the basipterygoid, process. thious palate. In fact the vomer is very broad, and in front unites with the broad maxillo-palatine plates, as in Dromceus; while behind * The only genera in which, so far as I know, this angle is somewhat greater than a right angle are Ocydromus and Didus. f Tinamus perhaps affords an exception to this character. + " On the Osteology of the Gallinaceous Birds and Tinamous " (Transactions of the Zoological Societv, vol. v., 1864). Sundevall, however, had already said of Tinamus, Rhynchotus, and Crypturus, " Struthiones parvos referunt." |