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Show 516 MR. A. H. GARROD ON THE ANATOMY [June 6, Menura superba, from the above description, is therefore acromyodian, although not typically Oscine. Atrichia rufescens presents precisely the same arrangement as Menura. There are three modified bronchial semirings, the third descending posteriorly, and the second expanded a short distance before it reaches its anterior termination, the anterior longitudinal muscle being there inserted. The posterior muscle, however, does not clearly separate into two before it reaches its points of insertion, which are identical with those in Menura. The lower tracheal rings are different, in that they are not flattened from above downwards ; they retain the characters of those above them to a great extent. The last forms the characteristic three-way piece. In Plate LII. figs. 4, 5, & 6 these points are clearly seen. Atrichia is therefore also Acromyodian, although far from being normally Oscine. It would require but little modification in either it or Menura to convert their syringeal muscular masses into more numerous independent muscles. In the Crow, Starling, and most of the other Oscines I have examined, the third semiring is the one to which the long anterior muscle runs, the long posterior not going beyond the second. This condition is just reversed in the two birds under consideration. In the Finches the arrangement described by Cuvier maintains, both anterior and posterior long muscles running to the third bronchial semiring. In Plate LII. fig. 7 the sternum of Atrichia is figured with the rudimentary clavicles (f), which are nothing more than granules of bone. No other Passerine bird wants the furcula, so far as is yet known. The manubrium sterni is not largely expanded. There is another feature in Passerine anatomy which has interested me considerably during m y investigations. It is the rule among birds, almost without exception, that the main artery of the leg is that which must be supposed to be represented in Man by the comes nerri ischiatici, it accompanying the sciatic nerve-the sciatic artery. The main nerve of the leg is the sciatic ; the main vein the femoral. The only known exceptions to this rule are the cases of the genus Dacelo among the Alcedinidae, and Centropus among the Cuculidae. In the former the femoral vein is replaced by the one which is intermediate in situation between its usual course aud the sciatic artery ; in the latter the sciatic artery is absent, and is replaced by the femoral *. In a certain few Passerine birds the main artery of the leg is the femoral, and not the sciatic. These genera are all members of the Oligomyodi of Miiller ; and the accompanying list contains the names of all the Oligomyodian species (taken from Messrs. Sclater and Salvin's ' Nomenclator Avium Neotropicalium' f) which I have had the opportunity of examining, with the results arrived at, as far as this peculiarity is concerned. * Proc. Zool. Soc. 1873, p. 629. t London, 1873. |