LEPIDOSIREN PARADOX A. 
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mesenteric and the iliac arteries (Text-fig. 2^ Coe. A., 8cl., A. 
mes., P. mes.y and 11. A.). Of these the limb vessels are paired, 
the others unpaired. Posterior to the subclavian arteries the 
aorta gives off segmentally arranged vessels (Text-fig, 2, 
Seg. ^4.), which in turn give branches to the spinal column, 
body-walls, and to the kidney and gonad. 
Lingual Arteries. — On either side the paired ventral 
aorta is prolonged forwards as the lingual artery (Text-fig. 2, 
L. A.) ] this vessel passes outwards and forwards along the 
floor of the mouth between the ramus of the jaw, to which it 
gives a branch, and the tongue. 
Carotid Arteries. — The dorsal aortic root on either side 
is prolonged forwards as the dorsal carotid artery (Text-fig. 
2, Car.) ; this vessel passes forwards a short distance in the 
roof of the mouth, as far as the anterior part of the auditory 
capsule; here it divides into an internal and an external branch 
('I’ext-fig. 2, Car. L, Car. e.). The external branch passes 
forwards slightly dorsally and outwards, accompanying the 
trigeminal nerve, with which it is distributed to the surface of 
the head. The internal branch passes dorsally a little, to the 
base of the brain itself. 
Pulmonary Arteries. — Two pulmonary arteries (Text-fig. 
2, P. A.) arise one on either side from the short common dorsal 
stem of the fifth and sixth aortic arches; both vessels extend 
for some distance dorsal to the oesophagus on either side of 
the aorta, but as they reach the lungs their positions relative 
to one another alter. Of the two vessels the left artery is the 
larger ; it passes backwards and inwards and curves from the 
left side round the ventral surface of the oesophagus to reach 
the ventral surface of the lungs, and then, after crossing 
ventrally to the left pulmonary vein, bifurcates, giving a 
branch to each lung. The right pulmonary artery is the 
smaller : on reaching the lungs it passes backwards and 
inwards, to the left of and ventrally to the coeliac artery, and 
divides into two branches, one to the dorsal surface of each 
lung. 
Coeliac Artery. — The coeliac artery (Text-fig. 2, Coe. A.) 
