OCR Text |
Show 1879.] TRACHEA OF THE GALLINAE. 379 slender first bronchial semiring, which is very concave upwards, interval between it and the last tracheal ring is conspicuously large and fusiform, one side of the small antero-median process and the outer border of the inferior angle of the corresponding truncated posterior termination of the last tracheal ring being its articulating spots. The semiring is not of uniform thickness, small expansions, not unlike the "tubercles" of ribs, occurring at a short distance from both ends, which mark the points at which the next semiring meets it and ceases. The second semiring is simple, except that it is slightly enlarged at its posterior extremity. The interval between it and its neighbours is extremely narrow. Fig. 34. Fig. 35. Front view. Back view. Aburria carunculata. The species I have examined are Crax globicera, C. carunculata, Pauxis galeata, 31itua tomentosa, Penelope jacucaca, P. cristata, P. superciliaris, Pipile cumanensis, and Aburria carunculata. In Penelope, Pipile, and Aburria the first bronchial semirings are thicker and stronger than in Crax and its near allies, their posterior articulations with the ends of the last tracheal ring being upon what becomes the outer, but normally would be the inferior surfaces of its juxtapessular terminations, because of a characteristic downward flexure of their expanded obtuse extremities. The lateral intrinsic tracheal muscles are thin, and run down to cease opposite the ring fifth from tbe bifurcation of the tube, as in nearly all Gallinaceous birds. I cannot trace any fibrous continuation to the lower rings from their muscular extremities. Incidentally it may be mentioned, with reference to the development of the extrathoracic tracheal loop in the Cracidae, that, as far |