OCR Text |
Show •879.] TRACHEA OF THE GALLINAE. 361 It develops a considerable angle on its convex border in front, the spot where the next semiring meets it. Behind ic is peculiar from its inconsiderable thickness, it meeting the corresponding extremity of the last tracheal ring for some distance, opposite which part it is so narrow that the expanded hinder end of the second semiring does not manage to reach it, and remains separated by a small interval. This second semiring meets it in front, and sends inwards beyond the articulating spot a pointed process of some length. The lower bronchial rings are similarly pointed and prolonged in front. The bronehidesmus is powerful, at the same time that its posterior margin is the place of insertion of the pair of contiguous powerful muscles that runs down the back of the windpipe, and spreads laterally so much as to bejust seen in the anterior view of the organ. The windpipe of Oreortyx pictus differs in detail from that of tbe bird just described. The penultimate and last rings of the trachea blend in the mid- anterior and posterior line ; whilst behind the antepenultimate does so also, articulating in front. The next four rings anteriorly are lozenge-shaped in the middle line, the six above which are uniformly thinned ; but the intervals between them are much less considerable than in Lophortyx californicus. Posteriorly there are no interannular intervals at all. The bronchial semirings, the posterior muscles, and the bronehidesmus are as in Lophortyx. In Arboricola atrogularis the bifurcating portion of the windpipe most closely resembles that of the American Quails. With no posterior interannular intervals, those in front are deep and twelve or so in number, being interrupted, in the case of that between the last and penultimate rings, by a large medio-anterior lozenge-shaped ossification which unites them, but continuous above except that a fine fibrous band runs up the tube, as in Lophortyx, previously described. The thinned antero-lateral element of the last ring has a slight special downward curve towards its inner end. In Oreortyx there is an indication of the same. The second bronchial semiring is prolonged inwards pointedly in front, and posteriorly does meet the first semiring to articulate slightly with it. In Coturnix communis, with which C. coromandelica agrees in every respect, the posterior surface of the intrathoracic portion of the trachea is seen to be formed by rings between which no interannular intervals exist, except as transverse lines. Anteriorly, however, the rings are very much thinner, becoming so abruptly at the side of the tube, and the intervals between them are nearly twice their depth, even more than that towards the bifurcation of the tube. Narrow medio-anterior perpendicular isthmuses of fibrous tissue connect the lowermost six rings. Laterally the penultimate ring is slightly upturned, more behind than in front. The anterolateral thin portion of the circumference of the last ring is decidedly convex downwards, as is also the first bronchial semiring and the second. The last tracheal ring sends downwards a medio-anterior oblong process, ossified in the adult, to the lower angles of which |