612 Mr. W. P. Py craft on the 



The apparent first bronchial ring is really made up of two 

 elosely apposed rings, succeeded by six or seven half hoops 

 moderately wide apart. The bronchidesmus is well developed. 



The tracheo-bronchialis muscle extends the whole length 

 of the trachea, terminating in a few delicate strands of 

 muscle inserted into the middle of what answers to the 1st 

 bronchial ring. Just before its insertion, near the bottom 

 of the syringeal box, it gives off a strong sterno-trachealis. 



It will be remarked that the syrinx of Acanthidositta is 

 peculiar ; it recalls that of Pipra on the one hand and of 

 Todus on the other, and differs widely from the typical 

 Synallaxine syrinx, which is tracheal. 



Forbes (2) described and figured the syrinx of Xenicus, 

 comparing it with that of Todus. He does not seem to have 

 examined the syrinx of Acanthidositta, and this may well 

 account for the lack of agreement between my observations 

 on the syrinx of this bird and the description and figures by 

 Forbes of the syrinx of Xenicus, which he assumed was the 

 same in both genera under consideration. 



In Xenicus, according to Forbes, the intrinsic muscle 

 terminates at the top of the syringeal box, as in Todus ; in 

 Acanthidositta it as certainly extends beyond this on to the 

 first bronchial ring, as already described. 



Judging by Forbes' s description (2), it would seem that 

 Xenicus is more degenerate, in so far as the musculature of 

 the syrinx is concerned, at any rate, than Acanthidositta. 

 Possibly, however, the differences between the syringes of 

 these two genera, as shown by my dissection of the last- 

 named, are apparent rather than real, the discrepancies 

 being due to our individual interpretation of the facts, which 

 are by no means easy to ascertain. The main point wherein 

 I differ from Forbes concerns the termination of the in- 

 trinsic muscle. According to Forbes, this terminates just 

 before reaching the top of the syringeal box. My dissections 

 seem to shew that this muscle ends, in the form of very 

 degenerate fibrous tissue, on the third bronchial ring. There 

 can be no doubt but that the figures of the syrinx of Xenicus 

 in Forbes's paper lose much of their value by their extremely 



