1879.] 



TRACHEA OF THE GALLING. 



379 



slender first bronchial semiring, which is very concave upwards, the 

 interval between it and the last tracheal ring is conspicuously large 

 and fusiform, one side of the small antero-median process and the 

 outer border of the inferior angle of the corresponding truncated 

 posterior termination of the last tracheal ring being its articulating 

 spots. The semiring is not of uniform thickness, small expansions, 

 not unlike the "tubercles" of ribs, occurring at a short distance 

 from both ends, which mark the points at which the next semiring 

 meets it and ceases. The second semiring is simple, except that it 

 is slightly enlarged at its posterior extremity. The interval between 

 it and its neighbours is extremely narrow. 



Fig. 34. 



Fig. 35. 



Front view. 



Aburria carunculaia. 



Back view. 



The species I have examined are Crax globicera, C. carunculaia, 

 Pauxis galeata, Mitua tomentosa, Penelope jacucaca, P. cristata, 

 P. superciliaris, Pipile cumanensis, and Aburria carunculaia. In 

 Penelope, Pipile, and Aburria the first bronchial semirings are 

 thicker and stronger than in Crax and its near allies, their posterior 

 articulations with the ends of the last tracheal ring being upon what 

 becomes the outer, but normally would be the inferior surfaces of 

 its juxtapessular terminations, because of a characteristic downward 

 flexure of their expanded obtuse extremities. 



The lateral intrinsic tracheal muscles are thin, and run down to 

 cease opposite the ring fifth from the bifurcation of the tube, as in 

 nearly all Gallinaceous birds. I cannot trace any fibrous continua- 

 tion to the lower rings from their muscular extremities. 



Incidentally it may be mentioned, with reference to the develop- 

 ment of the extrathoracic tracheal loop in the Cracidse, that, as far 



