THE RESPIRATORY ORGANS. S7 



found to open into the furthest right subdivision of the 

 ventricle — the cavum pulmonale. Pass bristles similarly 

 along the aortae ; both will be found to open into the 

 median division of the ventricle — the cavum venosum ; 

 the opening of the left aorta being to the right of that 

 of the right aorta. Slit open the arteries, and observe 

 the valves at their mouths. 



146. Observe the Trachea ; note the way it is curved 

 when the neck is retracted, and its division on the right 

 side of the retracted neck into the right and left bron- 

 chus, each of which enters its own lung near the ante- 

 rior end, alongside the pulmonary artery and vein. 



147. Remove the hyoidean apparatus, with the 

 tongue, larynx, and a bit of the trachea attached. To 

 do this, divide the muscles, etc., between the rami of 

 the lower jaw and the anterior horns of the hyoid, so as 

 to open the buccal cavity from its floor ; then seize the 

 tongue with forceps and draw it out ; note the stylo- 

 hyoid ligament passing from the anterior horn of the 

 hyoid to the base of the skull. Divide it on each side ; 

 cut through the trachea about an inch behind the lar- 

 ynx, also any other connecting bands, and remove the 

 mass. Note the eminence at the back of the tongue 

 (4, c), and the slit {aditus laryngis) in it which leads into 

 the larynx. Separate the firm edges of the slit, and 

 examine the interior of the larynx, wiping out mucus, 

 etc., with a little bit of sponge held by a small pair of 

 forceps. 



148. Put the removed parts away to macerate in 

 water for a few days ; then separate and examine the 

 3* 



