20 



WILLIAM A. LOCY AND OLOF LARSELL 



Figure 45 shows the surface aspects in the adult of the recur- 

 rent bronchi of the abdominal and posterior intermediate air-sacs 

 to the bronchial tree and the way in which their stems connect 

 with the air-sacs represented. In this metallic cast the abdomi- 

 nal air-sac was only partly injected so that the proximal end 

 only is shown. It will be seen that the main recurrent bronchi 

 of the abdominal air-sac extend more than one-third of the way 



- 0. Abd 



Pig. 53 Diagram of a ventral view of the lungs on the first day after hatching. 

 The moieties of the interclavicular sac have united on each side and those of the 

 right and left lung have come into contact, being separated only by a temporary 

 partition wall. Shows also the nature of the orifices into the air-sacs. Cervical 

 sac not represented. 



toward the ventral anterior border of the lung before branching 

 to any marked extend. The rami into which these recurrent 

 bronchi finally break up anastomose with the numerous air- 

 passages in the lateral facet of the lung. 



Summary. Summarizing our observations we conclude that: 

 1. The recurrent bronchi are offshoots from the air-sacs lead- 

 ing into the lung parenchyraa, and the air-sacs in turn, except 

 the abdominal (from the mesobronchus) , are the expanded ter- 



