OCR Text |
Show 1895.] LORIUS FLAVOPALLIATUS AND PSITTACUS ERITHACUS. 335 what hourglass-shaped, with two slight concavities to articulate with corresponding slight convexities on the pleurosteon (piu) of the sternum. They increase rapidly in length from the first to the fifth; they are also somewhat longer, relatively, in L. flavopalliedus than in P. erithacus, especially the first on either side. In P. erithacus it is shorter than the distance from the apex of the first thoracic rib to the ventral margin of the uncinate process. In L. fiavopalliatus it is longer than that distance, and the same is the case as regards the three following sternal ribs in that species. In P. erithacus the three following ones about equal the length of their corresponding thoracic rib, from its apex to the ventral margin of the uncinate process. Fig. 21, m Ventral aspect of sternum of Psittacus erithacus. m. Manubrium. p. Lateral angle. pn. Pleurosteon. ca. Costal angle. do. Defect of ossification. h. Muscular impression. The sternal rib corresponding with the first floating thoracic rib does not articulate with the sternum, but rather applies itself to the postaxial surface of the fifth sternal rib near to its distal end. |