PLATANISTA. 457 



inch in length by O'lO in breadth in some instances, but occasionally they are so small 

 that they are liable to be overlooked. The epiglottidean when removed from the 

 thyroid cartilage and its arytenoid surface placed flat, resembles a heel-less boot, the 

 dorsum being the anterior border of the cartilage, and the sole corresponding 

 to the concave portion, which latter is applied to the arytenoids. The toe, of course, 

 is enormously expanded, with two small lateral horns, and is the apex of the cartilage. 

 The back of the boot, the surface applied to the thyroid, is concave, but filled up 

 in the recent state with the strong attachment of the thyro-epiglottidean ligament. 

 The anterior angle of its thyroid surface, when denuded of membrane, is seen to be 

 formed by a distinct cartilage triangular in form, and measuring nearly an inch in 

 length and 0*25 inch in its greatest breadth. It occupies a position on the epiglottis 

 in which some such arrangement would be expected, for it occurs opposite to that 

 part of the cartilage which faces the body of the arytenoids and fills up a gap between 

 them, the mobility caused by the fibrous attachment of the two aiding the perfect 

 apposition of the aryteno and epiglottidean mucous surfaces. This supernumerary 

 cartilage is tipped at its rounded margin by one or two minute but distinct cartilages. 

 The anterior margin of the cartilage at its extremity divides in two, and forms 

 a notch through which passes the aryteno-epiglottidean ligament ; this passes back- 

 wards to be attached along the dorsal aspect of the body of the thyroid, as far as the 

 notch. The sides of the cartilage of the epiglottis are covered by numerous pits for 

 the reception of glands. 



Trachea. — Before its division this is very short, the bronchus to the apex 

 of the right lung being given off a couple or three inches from its commencement ; 

 the bronchi to the middle and base of the right lung and to the left lung respect- 

 ively, being given off, as it were, by the conjoint bifurcation of the rest of the tube. 

 On reaching the apex, the first bronchus divides into two principal branches, which 

 follow the method of division of the trachea, i. e., divide each into three branches. 

 The second bronchus when it reaches the lung gives off three small branches, one after 

 the other, to the external portion of the penultimate fourth of the organ, the main 

 portion being directed to the middle of the lung, and dividing dichotomously. The 

 third or left bronchus divides into two before it reaches the lung ; the left branch 

 being directed to the apex and the right to the rest of the lung. 



The diameter of the trachea is greatest transversely. The cricoid cartilage is 

 succeeded by a broad flattened ring of cartilage, varying according to the age of the 

 individual from 0*25 inch to one inch in antero-posterior extent. On its side it is 

 sometimes cut into by a fibrous band, so that it is quite possible that in some instances 

 it may be much narrower by a separation of a portion of itself as a separate ring ; and 

 on its dorsal surface it shows a distinct tendency to break up into small plates. It is 

 succeeded by a flattened band of cartilage which, commencing by a free end on the 

 dorsal surface of the right margin of the trachea, passes round to the left, i. e., along 

 the ventral surface till it reaches the left margin of the tube. There it suddenly 

 bends on itseH and passes behind its first portion, again to the right, along the 

 ventral surface, so that it does in no way form the dorsal wall of the tube. But two 



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