PROF. OWEN ON THE ANATOMY OF THE INDIAN RHINOCEROS. 47 



There was no trace of a valve at the orifices, either of the inferior cava or coronary 

 vein ; the latter easily admitted the end of the fore-finger. In the right ventricle, the 

 tricuspid valve presented the following attachments : — its strong chordae tendinepe were 

 distributed to three obtuse and transversely oblong columnse carnese, one rising from the 

 external or moveable wall, a second from the septum, and a third smaller one from the 

 anterior interspace between the fixed and moveable wall : the tendons diverged from 

 each column to the two contiguous moieties of the divisions of the tricuspid valve ; a 

 provision which ensures the simultaneous action and the outstretching of these three 

 membranous processes. There were besides two smaller columns placed opposite to 

 each other, one on the free and the other on the fixed wall of the ventricle ; they were 

 connected together by a single strong tendon passing across the ventricular cavity from 

 the apex of one to that of the other. 



The mitral and semilunar valves offered nothing unusual. 



The aorta, after giving off two coronaries, each of which freely admitted the fore- 

 finger, ascended and divided at the summit of its arch into the descending aorta and 

 a smaller trunk supplying the head and anterior extremities. The vessels immediately 

 derived from the ascending division were the two internal thoracics', the brachials, and 

 the common trunk of the two carotids. 



Each lung was divided into a small upper and a large lower lobe ; the right lung gave 

 off in addition a transversely elongated narrow azygos lobe. The superior lobe of each 

 lung was characterized by numerous deep marginal notches, which gave it an appendicu- 

 lated character. The lining membrane of the branches of the bronchise presented very 

 strongly marked longitudinal ruga; ; that of the trachea was similarly disposed. After 

 reflecting the pleura from the surface of the lung, a thin extensible stratum of condensed 

 cellular tissue continuous with the interlobular cellular tissue could alone be perceived. 

 Between the pleurae and the parietes of the chest was much elastic tissue. 



The cartilaginous hoops of the trachea are stout and close-set ; they meet posteriorly, 

 but their extremities do not coalesce; th3ir number was 31. The diameter of the 

 windpipe is two inches and a half, being not greater than that of the Lion. 



The larynx consists of the thyroid (PI. XV. th), cricoid {lb. c), and arytenoid {lb. a) 

 cartilages, of the epiglottis {lb. e), and of a small sesamoid fibro-cartilage {lb. fig. 1, k) 

 developed in the commissure of the ' arytenoidei transversi' and ' obliqui,' here blended 

 together ; but there is no trace of the cartilages of Santorin or Wrisberg. The wings 

 of the thyroid cartilage meet at a slightly obtuse angle, contrary to their usual dis- 

 position in the Hog tribe and Ruminants : there is no notch at the upper margin of 

 the anterior median line ; but there is a considerable triangular vacancy below, filled 



' The intercostal spaces above or anterior to the heart, are numerous in proportion to the narrowness of the 

 chest, which obliges the heart to be placed nearer the diaphragm; and the internal thoracics, which are of insig- 

 nificant size in Man, are there largely developed in order to supply those intercostal spaces, which, from the 

 position of the heart, cannot receive their arteries directly from the trunk of the aorta. 



VOL. IV. — PAKT II. I 



