356 PROF. A, H. GARROD ON THE [Apr. 1, 



ring of the trachea. The last tracheal ring, it must not he forgotten, 

 is incomplete behind. 



The first bronchial semiring — for in no Gallinaceous birds are 

 any of tbe bronchial rings complete — articulates at both its extre- 

 mities with the last tracheal, anteriorly along the side of the oblique 

 median process, posteriorly with the lower angle of its square-cut 

 termination. Both ends are slightly expanded and obliquely trun- 

 cated, their acute upper angles being their articulating spots. The 

 lower margin of the last tracheal ring being concave downwards 

 and slightly uptipped laterally, whilst the first bronchial semiring 

 descends slightly from its attachments outwards, a considerable 

 membranous interannular interval is left. The second bronchial 

 semiring is simple, free, and slightly expanded posteriorly. In 

 front the third was bifurcated in both bronchi, on one side each 

 branch being further subdivided. The depth of the bronchial 

 interannular membranes is about the same as that of the semirings 

 themselves. 



Between the membranous inner wall of one bronchial tube and 

 the same part of the other there is a dense fibrous band of union, a 

 short distance below the bifurcation of the windpipe, and generally 

 on the level of the two or three semirings below the second. This 

 band is, 1 believe, always to be found in birds (it will be termed the 

 bronchidesmus in this communication) developed to a greater or 

 less extent. Being of fibrous tissue and connected with the mem- 

 branes of the neighbourhood, anatomists have removed it whilst 

 dissecting the organ for examination. Its importance, however, is 

 more considerable than might be at first imagined ; and I only regret 

 that in many of the subjoined descriptions I took no note of it. In 

 birds like the Tetraonidse the bronchidesmus is so strong that it 

 cannot escape special observation. 



The adult female presents no modifications of importance. The 

 penultimate and last tracheal rings are relatively a little smaller 

 and have blended in front in the middle line, whilst all trace is lost 

 of the shape of the posterior termination of the pessulus. The 

 articulating surfaces of the first bronchial semiring have become 

 slightly more considerable. 



The adult (male) P. nigripennis differs in that the antepenulti- 

 mate tracheal ring blends anteriorly with the penultimate, at the 

 same time that there is a greater fusion between the penultimate 

 and last rings, all three apparently blending behind as well. The 

 interannular interval between the last tracheal ring and the first 

 bronchial semiring is reduced to little more than a line, and the 

 bronchial interannular intervals are very small. 



It is to be specially noted that in the genus Pavo the second 

 bronchial semiring, by not articulating with the one above it at 

 either end, does not participate in the formation of the specialized 

 lower larynx. This is a feature indicating non-elaboration of the 

 organ. No other Gallinaceous bird with which I am acquainted 

 resembles Pavo in this respect. 



In Caccabis rufa the thoracic extremity of the trachea is perfectly 



