70 Appendix. 



except iu a small part, equal to about oue sixth the breadth of each semi-ring, one third distant 

 from their anterior ends, where they retain their primitive cartilaginous structure (m'tZe Plate VII, 

 figs. 7 and 8). 



The lateral muscle of tlie trachea is of considerable breadth, being most developed anteriorly, 

 those of the opposite sides coming nearly into contact in the middle line in fiont. Opposite the 

 tracheal ring seventh from the bottom, the small steruo-trachealis is differentiated off from the 

 posterior portion of this muscle, by fai- its larger anterior jsart 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 my 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 ling, 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. Chiromachaeris manacus, 

 according to the description given by MiiUer, agrees exactly with this species, as far as its syrinx 

 is concerned. 



lIetero2)dma verae-pacis is most simple iu its voice-organ. The single broad lateral muscle' 

 of each side of the trachea continues down to the middle of the second bronchial semi-rings, 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. 



Iladrosiomus aglaiae is a bird iu 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 modified, except the last, which is developed into a three-way piece from tlie presence of 

 a bar runuinsj from before backwards at the middle of the lower margin. The first bronchial 

 half-ring is of the same flattened and deep nature as the tracheal rings, and, like them also, is 

 not separated from the three-way piece by any interval. To its antei'ior end, on each side, as 

 well as to the front of the three-way piece, the intrinsic muscle is attached, which descends, broad 

 and thin, down the front of the lower part of the trachea, in contact with its fellow of the opposite 

 side, there to terminate (;vide Plate VII, fig. 9). 



The second bronchial semi-ring is not modified. It is separated by a short interval from 

 the fir;jt, and by a strikingly considerable one from the third, which is the commencement of 

 the normal bronchus. I could not find that the muscles of the .syrinx sent any fibres to this 

 second ring, as in Pachyrhamplius alricapillus, described by Miiller, although otherwise this 

 structure is almost identical in the two birds. If they are present they must be extremely feeble ; 

 and the relative distances of the upper bronchial semi-rings favours the view that some special 

 arrangement exists. 



The account, above given, of the voice-organs iu the aberrant Passeres in question, is entirely 

 confirmatory of the results arrived at by Johannes Miiller. Both I/ylactes and Grallaria are com- 

 pletely tracheophone, as he predicted they would be found to be, although they agree with one 

 another, and differ from those previously described iu having the syringeal end of the trachea 



