490 



WILLIAM A. LOCY AND OLOF LARSELL 



laterohronchi are developed, but not simultaneous'y, and they 

 arise as buds from the lateral wall of the embryonic vestibulum. 

 The first two (fig. 30, Lat. 2 and 3) arise at the stage of six days 

 six hours. These are, in reality, numbers two and three — nmn- 



Par.-: 



V Par. 



P'ig. 39 Latero-posterior view of the right lung of late ninth day of incuba- 

 tion. Sho\v.s the beginning of recurrent bronchi on the abdominal and the pos- 

 terior air-sacs. 



Fig. 40 Lateral view of the left lung of the same specimen. Illustrates the 

 five air-sacs and primordia of recurrent bronchi of the four air-sacs possessing 

 them in the adult. Rec.Br., recurrent bronchi, other reference letters as under 

 figure 35. 



ber one arising later in front of number two. They elongate in 

 the latero-ventral plane, so that near the close of the seventh 

 day they are distinctly prominent (fig. 32, 6 days, 20 hours). 

 At the beginning of the ninth day (fig. 36) both two and three 



