300 PROF. OWEN ON THE ANATOMY 
a. The sterno-trachealis muscle: bristles are seen passing from the external 
branch of the bronchus into the three anterior air-sacs. 
5. Front view of both lungs. 
a. The anterior or short pulmonic bronchial tube. 
b. The posterior or long pulmonic bronchial tube. 
c. The bronchial tube of the air-sacs. 
PLATE LI. 
Fig. 1. A dissection, showing the diaphragm of the Apteryz. 
«. The two crura of the vertebral portion or lesser muscle of the diaphragm. 
G, 8. Fasciculi of the costal portions of the diaphragm. 
a. The pericardium covering the apew of the heart, and protruding through 
the anterior fissure of the diaphragm. 
b. The wsophagus. 
. The trunk of the cceliac axis protruding through a foramen in the ex- 
panded central tendon of the diaphragm. 
m. The mesenteric artery. 
n. The abdominal aorta. 
o. The spermatic artery. 
p, p- The femoral arteries. 
q, q. The renal arteries. 
x, r. The ischiadic arteries. 
s. The sacro-median artery. 
Fig. 2. Front view of the heart. 
a. The right ventricle. 
b. The right auricle. 
c. The pulmonary artery. 
d. The arterie innominate. 
e,e. The internal thoracic arteries. 
f,f. The brachial arteries. 
g. The carotids. 
3. The heart, dissected, to show the interior of the right auricle and ventricle. 
b. The inferior vena cava. 
c. The left superior cava. 
d. The right superior cava. 
e & f. The semilunar valves, between the sinus and auricle. 
g. The right auriculo-ventricular valve. 
h. The left auricle. 
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