318 CHIKANOSUKE OGAWA 
DIVISION OF THE FINER RESPIRATORY TUBULES 
According to B. N. A. there are two divisions of the finer 
respiratory passages, namely, bronchiolus respiratorius and duc- 
tulus alveolaris. The space from which the end branches divide 
themselves is designated by Miller the atrium. ‘This name is 
adopted in several text-books. Several names are proposed for 
the end branches of the alveolar ducts—sacculus alveolaris, 
Vig. 3 Negative model including two air-sacs adjacent to pleura. Original 
model 100 * enlarged. Figure reduced to 50 X. 
infundibulum, end-sac, air-sac, and so on. Some authors (Cru- 
veillier and Brass) use the word ‘infundibulum’ loosely for 
ductulus alveolaris. Furthermore, Nicolas and Testut rather 
unnecessarily give the name vestibule to the space between the 
bronchiolus respiratorius and the ductulus alveolaris. 
Now I will come to the detailed description of the alveolar 
ducts, 
