98 The Development of the Lungs 
the same lines followed in embryonic life. The chief changes occur in 
the respiratory lobules. The bronchiolus (Fig. 290) is clothed by 
eubical epithelium surrounded by a well-marked basement membrane 
Trexr Fic. 29. Sections of a portion of the lobule of the lung of a pig, two 
days old. Same preparation as used with tissue shown in Fig. 28. X 130. 
?=lymphatics. b—bronchiolus. br=—bronchiolus respiratorius. 
tulus alveolaris. a=atria. sa—sacculi alveolares. 
i= duc- 
c—alveoli pulmonaris. 
