THE RABBIT. 325 



XXXIV. Carefully remove from the body the heart 

 and lungs, together with the posterior end of the 

 trachea and recognisable portions of the aorta 

 and venae cavae. Fasten out the organs under 

 water, with their dorsal surface uppermost, and 

 make out : 



306. The course of the pulmonary arteries and 

 veins : the arteries remain single until they reach the 

 lungs; the veins are two from each lung, and enter the 

 left auricle separately, in the U-shaped space between the 

 two precavals. 



XXXV. Cut through the pulmonary arteries and veins 

 close to the lungs, and separate the latter from the 

 heart : make out : 



307. The division of the left lung into two lobes, an 

 anterior and a posterior : the former is deeply divided 

 by a transverse fissure. 



308. The division of the right lung into four lobes, called, 

 passing from before backwards, the anterior accessory ^ 

 the anterior, the posterior, and the posterior acces- 

 sory : the " accessory " lobes are considerably smaller than 

 the other two : the posterior accessory is situated internal to 

 the root of the lung and rather to the left side of the thoracic 

 cavity. 



309. The cartilages of the trachea and bronchi, 

 incomplete rings surrounding the ventral and lateral aspects 

 of the tubes, but leaving their dorsal sides unstrengthened. 



310. The division of the left bronchus into two tubes, one for each 

 lobe. 



311. The subdivisions of the right bronchus: it first gives off a 

 branch on the outer side to the anterior accessory lobe, then one on the 

 ventral side to the anterior lobe, and finally divides into two branches for 

 the posterior and posterior accessory lobes. In some instances the 



