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Show 1867.] PROF. HUXLEY ON THE CLASSIFICATION OF BIRDS. 471 sible, for example, to restrict a term so commonly used in a wide signification as Passeres, to the sense in which Sundevall employs it. Muller divided the whole of the Lnsessores, according to the structure of the lower larynx*, into O S C I N E S or P O L Y M Y O D A E (of which Sundevall's "Passeres" form one family-the Fringillidee), having the lower larynx formed partly by the trachea and partly by the bronchi, and possessing five or "six pairs of muscles attached to the ends of certain of the bronchial rings; T R A C H E O P H O N A E , with the lower larynx formed exclusively by a modification of the lower part of the trachea; and PICARIAE, with the larynx either partly tracheal and partly bronchial, or wholly bronchial and with not more than three pairs of muscles. Under the head of Picariae, however, Muller included the Cypselo-morphae, Coccygomorphae, and Psittacomorphse, as well as the two i*Egithognathous families Tyrannidee and Ampelidce; and thus a group of "Picariae" very different from that of Nitzsch was established. Later authors, adopting Muller's term of Tracheophonae, have unfortunately extended the group so named to include the Tyrannidee and Ampelidce, dividing the whole of the " Passeres" into C A N O R AE and TRACHEOPHONE. Burmeister, for example, proposes this arrangement in his excellent monograph on Coracina scutata, and speaks of that bird as one of the Tracheophonae; whereas his account of its larynx shows that it is altogether dissimilar to the tracheal lower larynx of the Myiotheridee, Scytalopodida;, and Anabatida;, in which alone that singular structure has been found. Miiller would have put Coracina among his Picariae. If for " Picariae" we substitute a name formed in a manner analogous to Polymyodse, viz. O L I G O M Y O D A E , the iEgithognathae would be divisible according to their laryngeal structure into three groups; and it becomes an important question how far the three divisions thus formed are natural, or present other differences beside those of the larynx. From this point of view, and regarded as primary subdivisions of the Coracomorphae, it seems to me clear that they are not natural. Burmeister has described Coracina ; I have examined Cephalopterus, Tyrannus, Eurylaimus, Pteroptochus, and Chasmorhynchus; and in no one of them does the structure of the skull differ so much from that of a typical polymyodian Coracomorph (e. g. one of the Corvidee) as does that of the also polymyodian Coccothraustes. Pipra resembles the Finches. The sternum in most of these genera has the same characters as, and presents no greater varieties than are met with in, the Poly-myodae. But among the Tracheophonae the small group of Scytalo-podidee, as Muller originally stated, have two notches on each side of * Though he wavers in bis estimate of the taxonomic value of these divisions. See his paper, " Ueber die bisher unbekannten typischen Verschiedenheiten, &c," Abhand. d. Berl. Akad. 1846, p. 307. |