136 The Development of the Lungs 
Fic, 11. Reconstruction of the bronchial tree of a pig 10 mm. long. 
Fic. 12. Dorsal view of the same reconstruction. 
Fic. 13. Reconstruction of the bronchial tree of a pig 12 mm. long. 
Fic. 14. Dorsal view of the same reconstruction. 
PEAT Hels 
Figs. 15-19. 
Fig. 15. Reconstruction of the bronchial tree of a pig 13.5 mm. long. 
Fie. 16. Dorsal view of the same reconstruction. 
Fic. 17. Reconstruction of the bronchial tree of a pig 15 mm. long. 
Fig. 18. Dorsal view of the same reconstruction. 
Fic. 19. Reconstruction of the bronchial tree of a pig 18.5 mm. long. 
PLATE ITI. 
Fig. 20. 
Fic. 20. Dorsal view of the same reconstruction. 
PEATE AVE 
Figs. 21-25. 
Fia. 21. Celluloid corrosion of the bronchial tree of a pig’s embryo 5 cm. 
long. X 2. 
Fig. 22. Celluloid corrosion of the bronchial tree of a pig’s embryo 7 cm. 
lone x2: ° 
Fig. 23. Wood’s metal corrosion of the bronchial tree of a pig’s embryo 
18 cm. long. 
In this specimen one lateral bronchus on each side is suppressed, giving 
five laterals on the right and four on the left, instead of the usual complement 
of six and five respectively. Ventral 3 on both sides is suppressed. Sub- 
stituting for these branches are ventral branches of the adjacent lateral 
bronchi, while on the right side a lateral division from the inferior branch 
of V. 2 also extends into the region usually supplied by right V. 3. 
Fic. 24. Dorsal view of the same preparation. 
Dorsal 3 on the left side is suppressed. It is compensated for partly by 
Dorsal 2 growing lower than usual and partly by branches from Medial 4 on 
that side. On the right side Dorsal 4 is reduplicated, the upper element 
growing dorsolateralwards, the lower directly dorsal. Medial 4 and 5 are 
present on both sides. 
Fig. 25. Wood’s metal corrosion of the lung of a suckling pig two days 
old. Ventral view. X 2. 
Ventral 2 is broken off to show the dorsal bronchi. In places where the 
metal has passed into the smaller bronchi, the dichotomy is well shown. 
The branches are schematic in their arrangement with the exception of 
Ventral 5 on the left side, which is reduplicated, and an extra irregular lateral 
branch is interpolated on the right side. 
