1882.] 
ORGANS OF APTERYX. 565 
Fig. 1. 
a/A 
Fig. 1. Respiratory organs of Apteryx ; and Fig. 2, of a Duck having the trunk 
of nearly the same dimensions. In each the vertebral column and 
the left wall of the thoracic and abdominal cavities are supposed to 
be removed ; while the median vertical septum, the right half of the 
oblique septum, and the air-sacs of the right side are left. The 
contour of the right lung is indicated. 
d. 1, dorsal margin of the lung; v.a.1, ventral angle of the lung; 
I, prebronchial, IT, infrabronchial, III, anterior intermediate, IV, 
posterior intermediate, V, posterior air-sac; 1, 2, 3, dissepiments. 
L.c, longus colli; V. s, vertical median septum ; 0. s, oblique septum 
Tr, trachea; Ao, aorta; c. a, cceliac artery ; m. a, mesenteric artery ; 
“ eo: m, smooth muscular fibres in the oblique septum of the 
uck, 
