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



up by dense elastic and aponeurotic membrane, to which yielding walls of the larynx 

 some of the fibres of the thyreo-arytenoidei muscles adhere. The arytenoid cartilages 

 are relatively of large size ; their base extends half-way across the aperture of the 

 larynx, and from the anterior extremities of these produced bases, the upper 

 (PI. XV. fig. 1, u) and lower (lb. v) 'chordae vocales' extend forwards to the thyroid 

 cartilage and base of the epiglottis. Only the anterior half, therefore, of the ' rima 

 glottidis' is bounded by vibratile vocalizing material, and the ordinary feeble bleat of 

 the Rhinoceros (like that of a calf) is what might be expected to be produced by such 

 a structure. 



On each side, between the upper and lower chordce vocales there is the opening of a 

 large sacculus laryngis, which communicates anteriorly with a crescentic fossa under 

 the base of the epiglottis. A ibid of membrane (Pis. X. & XV. I) extends on each side 

 from a small fibro-cartilaiic (/), at the inner or under side of the base of the epiglottis, 

 downwards, inwards, and forwards to the anterior termination of the chordse vocales, u 

 and V : these oblique folds form the inner or posterior walls of the anterior fossse of the 

 sacculi laryngis. 



The anterior or superior labia (PL XV. fig. 2, m) of the glottis form two broad, thick, 

 slightly everted folds of mucous membrane. 



In the mass of muscles (PI. XV. fi^. 2, o, o) attached to and passing between the 

 arytenoid cartilages, there are developed about twelve tendons which radiate to be 

 inserted into the central sesamoid cartilage before mentioned. 



The epiglottis (Pis. X. & XV. e, e) is of a triangular figure, with the pointed apex 

 curved forwards, and having strong glosso-epiglottidei muscles attached to it. 



The thyroid gland consisted of two elongate, subtriangular lobes extending from 

 the sides of the larynx to the fourth tracheal ring ; diminishing as they descend and 

 united by a very thin and narrow strip continued between their inferior extremities, 

 obliquely across the front of the trachea. The structure of this body is more distinctly 

 lobular than is usually seen ; a small compact yellow glandular body was attached to 

 the thyroid at the point where the veins emerge. 



Part IV. 



Generative Organs. 



Male organs. — The cremaster is a very powerful muscle, and consists of coarse 

 carneous fasciculi in two flattened masses, one crossing the other obliquely as they 

 escape with the spermatic chord beneath the arch of the abdominal I'ing. A cluster of 

 lymphatic glands with much tough elastic cellular tissue fill up the rest of the ring. 

 The cremaster at this part measures one inch and a half in breadth and half an inch in 

 thickness. 



