Mr. Yak HELL on the Tracheœ of Birds. 379 



The Crested Pintado of Africa, the Numida cristaia of Pallas, 

 described and figured in Dr. Latham's General Synopsis, vol. iv. 

 p. 638, and in his General History, vol. viii. p. 148, exhibits 

 an extraordinary structure, to which I shall first advert. That 

 part of the os fiirciila, or merrythought as it is more commonly 

 called, which in our common Guinea Fowl consists of a single tiat 

 blade descending from the apex or junction of the two branches, 

 is in this bird double, one side appearing to extend from each 

 branch ; it is also somewhat circular, and united at the edges 

 throughout the greater part of the circumference, forming a 

 socket or pouch. The trachea, quitting the neck of the bird at 

 the lower curve of the cervical vertebrae, passes downward be- 

 tween the branches of the furcula, enters the pouch at tiie lower 

 part of the orifice, traverses the inner surface, and issuing from 

 the upper part, rises with a circular sweep, upward and forward 

 to the projecting anterior portion of the sternum, over which it 

 turns backward to pass into the body ; guided in its course by 

 two semi-transparent membranes, stretching from this projection 

 of the sternum to the head of each clavicle. 



If a line be drawn from the commencement of the trachea, as 

 shown in the figure, to the bronchia, passing between the sca- 

 pula% it will describe the situation of the trachea in our common 

 domestic Guinea Fowl, and the variation of the crested bird will 

 appear the more extraordinary by comparison. 



For the opportunity of figuring this singular structure, I am 

 indebted to the liberality of the Board of Curators of the Royal 

 College of Surgeons, and to the friendship of Mr. AV. Clift, jun., 

 for a beautiful drawing from a specimen in the Museum of the 

 College, the only one I ever had an opportunity of examining. 

 From that drawing the one now annexed is a close copy. 



M. Temminck has described this bird in his Histoire Nafu^ 

 relie Générale des Pigeons et des Gallinacés, vol. ii. p. 448, 



under 



