Anatomy of the Hoaizin. 



285 



tare of the subject, and the work of previous writers appears 

 to he entirely ignored ; nor can this omission be excused on 

 the ground that Dr, Young's description is so complete as 

 to render useless any reference to older writers. The syrinx, 

 w liich has been well figured (in two aspects) and described by 

 Prof. Garrod*, is represented by a small f and very inaccurate 

 drawing. The only description of the windpipe is as follows 

 (p. 172) : — "The wdndpipe, after it enters the chest, gives 

 off on each side one small branch, and passing on terminates 

 into {sic) two tubes.^' Apart from the error contained in 

 the first sentence (the " branches " are presumably the sterno- 

 tracheal muscles, but are represented in the plates as if they 

 were actually branches of the trachea itself !), it seems a waste 

 of space to state that the trachea divides into two bronchi ; 

 for this fact is not of any interest as a contribution to the 



structure of the genus! 



Fiff. 2. 



Opisthocomus cristatas. 

 Left Manus of Chick from outside : i, pollex ; ir, index. 



JVinff of young Opisthocomus. 



The external characters of the wing of the young bird are 



illustrated in figs. 1 and 2 of the plate which accompanies 



Dr. Young's paper, and in woodcut, fig. 2, of the present 



article. The most remarkable point in the structure of this 



* " Notes on Points in the Anatomy of the Hoatzin {Opisthocomus 

 cristaf.us);' P. Z. S. 1879. p. 109, and Coll. Papers, p. 465. 

 t Loc. cit. pi. viii. fig. G. 



