OCR Text |
Show 372 PROF. A. H. GARROD ON THE [Apr. 1, chial semirings blend with it laterally. Laterally, the separation between the last and penultimate rings is feebly indicated, as it is posteriorly by the non-ossification of the latter, notwithstanding the blending of the two. Posteriorly the oblong ossified cartilage, with its unossified and slightly indented upper margin (the part formed by the penultimate ring), is joined by the slender pessulus in the middle of its lower edge, whilst it is with its lower extreme angles that the simple posterior extremities of the first bronchial half-rings blend, the same parts of the second semirings not participating in the fusion, and being almost if not quite free, as are those below it at both ends. All the upper bronchial semirings are slender, strongly convex upwards, and separated by intervals not greater than their depth. The interval between the last tracheal ring and the first semiring, to which it is united both in front and behind, is fairly deep and crescentic. The antepenultimate ring is very much slenderer than the one below it, from which it is separated by a large interannular interval, deeper in front than behind on account of the obliquity of its plane. Anteriorly it is very shallow and insignificant; and it gradually enlarges as it goes backwards. The ring above it is scarcely different, but slightly less oblique, the interannular interval between it and the fifth from the end being slightly less than that next lower down. This fifth ring first gives indications of a latero-posterior deepening, with a corresponding reduction of the interannular interval and the formation of an antero-median horizontal fusiform space, the only remains of the interannular interval recognizable higher up, and extending into the cervical portion of the windpipe. Ceriornis temmincki differs from all other Gallinae examined by me, except Francolinus vulgaris, in that the third bronchial semiring articulates with the second, and so participates in the formation of the specialized organ under consideration. None of the tracheal rings are narrowed; and there are consequently no interannular intervals of any kind, if we except the one on each side of a narrow anterior isthmus which runs between the penultimate and the last ring. This interval is guttate in shape, on account of the slight upturning of the lateral element of the last ring, the antero-median part of which is expanded, almost exactly as in Euplocamus, into a quadrate cartilage. The pessulus at its posterior extremity is unattached, though situated as usual. Its freedom depends upon the fact that the penultimate as well as the last tracheal ring is incomplete behind, the end of the pessulus filling the deficiency and just touching the lower margin of the complete antepenultimate ring. This may possibly be the normal arrangement, all others resulting from subsequent consolidation. The first and second bronchial semirings are very much alike. The relations of the upper of them to the ring above, as well as those of the lower to the ring below, are almost identically those of Euplocamus; whilst posteriorly they consolidate together for one half their length, a small elongate fusiform interval existing external to their anterior fused extremities. With the lower of them the slightly-bowed third semiring articulates |