14 



WILLIAM A. LOCY AND OLOF LARSELL 



iiig of a dorso-lateral view of the lung and shows the relations of 

 the recurrent bronchi of the two posterior air-sacs at the close of 

 the fifteenth day of incubation. The recurrent bronchi are rep- 

 resented black and the other air passages in stipple. 



The distal tips of the longest recurrents of the abdominal air- 

 sac have anastomosed with the latero-ventral parabronchi of 



V-P.lntSc. 

 -[- Abd.Sc. 



Fig. 51 Latero-ventral view of the lungs and air-sacs of a fifteen day embryo. 

 Figures 48, 49 and 50 should be compared to show the progressive development 

 of the air-sacs and the way in which the four moieties of the interclavicular be- 

 come united. 



the first entobronchus. The more dorsal branches unite with 

 parabronchi of laterobronchi. It is worthy of notice that the 

 main stems of the first and second groups of recurrent bronchi 

 of the abdominal sac have united so that the second group appears 

 to be a branch of the first. By reference to figures 39 and 40 it 

 will be seen that the two groups were originally separate. By 



