1879.] TRACHEA OF THE GALLING. 359 



ring is much narrower and meniscoid. The second semiring itself 

 is strongly convex downwards, articulating behind by its extreme 

 end with the ring above, but in front continuing onwards as a 

 triangle beyond the articular point into the internal bronchial mem- 

 brane a short distance. The anterior terminations of the few lower 

 bronchial semirings are similarly pointed ; and posteriorly they run 

 inwards (especially the fourth and fifth) considerably more than 

 do semirings one and two. 



Polyplectron chinquis so closely resembles Argus in all respects 

 that no description of it is needed. The first and second bronchial 

 semirings are proportionately a little stronger ; the antepenultimate 

 tracheal ring does not actually fuse with the penultimate, and in 

 one specimen the pessulus, instead of blending with the penultimate 

 ring behind, runs upwards cuneately between the separated ends of 

 that ring to touch the lower margin of the antepenultimate ring. 

 From this and other facts pointing in the same direction, to be 

 mentioned subsequently, it may, with much probability, be inferred 

 that this arrangement just mentioned is the typical one, consolida- 

 tion of the pessulus with the posterior extremities of the penultimate 

 tracheal ring having occurred in those cases where, among the 

 Gallinse, that bar is found connected with it. 



In Ithayinis geoffroii ( tf adult) there is a transversely fusiform 

 median interannular interval between the lower tracheal rings an- 

 teriorly, entirely absent behind. The antepenultimate and penulti- 

 mate rings are slightly separated throughout, most at the sides, 

 whilst between the penultimate and last rings — fusing though they 

 do in the middle line anteriorly — there is a slight elongated oblong 

 interval on either side of the fused isthmus, extending outwards as 

 far as the lateral margin of the tube, but not further backwards. 

 The pessulus gives no indication of separation from the penultimate 

 tracheal ring posteriorly, whilst anteriorly it springs from the last 

 ring, between which and the first bronchial semiring there is a con- 

 siderable interval. This semiring is somewhat squared, sending up 

 processes (an anterior and a posterior) of no great length to arti- 

 culate with the last tracheal ring, the second semiring (scarcely 

 differing from the third) just touching its two angles sufficiently 

 for it to be said that it does articulate with it. In this species the 

 lateral sterno-tracheal muscle terminates inferiorly in a peculiar 

 manner. It is constituted of two parts, an outer and an inner. Of 

 the inner, which is also divided below into two, the median portion 

 ceases at the twelfth ring from the bifurcation, opposite which spot 

 its outer moiety sends downwards a special thin extra broad fasci- 

 culus to join the undivided outer main element of the muscle just 

 before it leaves the windpipe, opposite its antepenultimate ring. 

 The nerve to these lower fibres is not small ; and from being super- 

 ficial — resting as it does on the muscles under consideration as they 

 descend — it disappears behind the special fasciculus above described 

 at the spot where that begins to run inwards towards its fellow, 

 which it does not meet. 



In Lophortyx californicus (adult male) there are no interannular 



