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Show 1877.] ANATOMY O F PASSERINE BIRDS. 525 Lipaugus cineraceus.-In this species the single specimen at my disposal, which Mr. Edward Bartlett has most kindly given me, has the lower part of the windpipe considerably damaged by shot. Nevertheless, as one side is comparatively uninjured, I have been able to make out the essential points in the structure of the syrinx, which does not differ much from that of Pipra leucocilla, as represented by Miiller1. The lowermost rings of the trachea are not peculiar, each one being deep, and meeting, at its superior and inferior margins, the rings above and below it. The first and second bronchial semirings resemble those of the trachea in their flatness, depth, and approximation, the third being the first normal bronchial ring. It, with those which follow, are sliglitly peculiar in that they are ossified throughout, except in a small part, equal to about one sixth the breadth of each semi-ring, one third distant from their anterior ends, where they retain their primitive cartilaginous structure (vide Plate LIII. figs. 6 and 7). The lateral muscle of the trachea is of considerable breadth, being most developed anteriorly, those of the opposite sides coming nearly into!] contact in the middle line in front. Opposite the tracheal ring seventh from the bottom, the small sterno-trachealis is differentiated off from the posterior portion of this muscle, by far its larger anterior part continuing downwards to become the intrinsic muscle of the syrinx, which ceases at its insertion into the anterior half of the third bronchial semi-ring. It exhibits no tendency to split into two as in Pipra leucocilla. It may be mentioned that the second bronchial semi-ring is somewhat expanded at its ends, intruding more into the membranous completion of the bronchial tube than do those which follow it. The damaged condition of m y specimen makes it impossible to determine whether the antero-posterior bar, which is situated at the point of bifurcation of the trachea, is formed by the last tracheal ring, or by the completion and junction of the first bronchial rings of either side. I am inclined to think it depends on the latter of these conditions. Chiromachceris manacus, according to the description given by Miiller, agrees exactly with this species, as far as its syrinx is concerned. Heteropelma verce-pacis.-It is Mr. Salvin whom I have to thank for a specimen of this species, as well as the next to be described, in spirit. Its voice-organ is most simple. The single, broad lateral muscle of each side of the trachea continues down to the middle of the second bronchial semi-ring, which is scarcely different from those below it either in bulk or appearance; and the one above it resembles it. There is, however, a considerable interval between it and the third, whilst it almost touches the first. None of the lowermost tracheal rings are peculiar in any way. Hadrostomus aglaiee is a bird in which the calibre of the lower end of the trachea is very inconsiderable, and the syrinx is correspondingly difficult to investigate. The tracheal rings are not modi- 1 Loc. cit. plate iv. figs. 9-11. |