532 RESPIRATORY SYSTEM OF THE HORSE 
curved part of the groove for the aortic arch is absent on the right lung, on which 
there is a groove for the vena azygos. Anteriorly there are grooves for the trachea, 
the brachiocephalic trunk, the anterior vena cava, and other vessels. 
Dorsal border 
Fic. 473.—Lerr LunG or Horse; Costa SURFACE. 
Specimen bardened in situ. 
Pulmonary 
Groove for artery Bronchus ; 
anterior Ci y \ Groove for vena azygos Ligament of lung (cut) 
vena cava ae ee NS ‘ 
Pulmonary veins 
Line of reflection of pleura 
Fic. 474.—Ricur Lune or Horse; MepiIasTINAL AND DIAPHRAGMATIC SURFACES. 
Organ hardened in situ. c,d, Grooves for deep cervical and dorsal veins. Arrows indicate canal for posterior 
vena cava between intermediate lobe and main part of lung. By an oversight the impression of the trachea is un- 
marked; it is dorsal to the groove for the vena cava. 
The dorsal border (Margo dorsalis) is long, thick, and rounded; it lies in the! 
groove alongside of the bodies of the thoracic vertebre.! } 
‘In some cases this border is cut into by a fissure which partly marks off the apex from the: 
body of the lung. 
