e aorta to the upper extremities. U, U, U, U, A
branch to the lower extremities. V, V, V, V, V, V, The capillary
vessels at the extremity of the branches of the aorta. W, W, The
descending vena cava. X, X, X, The ascending vena cava.

In Figs. 1, 2, 3, the course of the blood through the circulatory
vessels is indicated by arrows.

PLATE VII.

THE PULMONARY CIRCULATION.

Fig. 1. 1, The right auricle of the heart. 2, The left auricle. 3, The
right ventricle of the heart. 4, The left ventricle. 5, The pulmonary
artery. 6, The branch of the pulmonary artery to the left lung. 7, The
branch of the pulmonary artery to the right lung. 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, Branches of the pulmonary artery in the right and left lung.
9, 9, 9, 9, 9, 9, Air-cells. 10, 10, 10, 10, 10, 10, 10, Small
pulmonary veins in the right and left lung. 11, The left pulmonary
vein. 12, 12, The right pulmonary vein.

Fig. 2. _An ideal View of the Pulmonary Circulation._ 1, 1, The right
lung. 2, 2, The left lung. 3, The trachea. 4, 4, 4, 4, 4, The right
bronchia. 5, 5, 5, 5, 5, The left bronchia. 6, 6, 6, 6, 6, 6,
Air-cells, with arteries and veins passing around them. 7, The right
auricle of the heart. 8, The right ventricle of the heart. 9, The
tricuspid valves. 10, The pulmonary artery. 11, 11, 11, 11, The right
pulmonary artery. 12, 12, 12, 12, 12, The left pulmonary artery. 13,
13, 13, 13, The right pulmonary vein. 14, 14, 14, 14, The left
pulmonary vein. 15, The left auricle. 16, The left ventricle. 17, The
mitral valves. 18, The septum between the right and left ventricles.

Fig. 3. _An ideal View of the Capillaries._ 1, 1, A branch of the
pulmonary artery. 2, 2, A branch of the pulmonary vein. 3, 3,
Capillary vessels between the artery and vein.

Fig. 4. _An ideal View of the Relations of the Bronchia, Air-cells,
Pulmonary Arteries, and Veins._ 1, A bronchial tube. 2, 2, 2,
Air-cells. 3, A branch of the pulmonary artery. 4, A branch of the
pulmonary vein.

PLATE VIII.

THE CEREBRUM, CEREBELLUM, SPINAL CORD, AND NERVES

1, The cerebrum. 2, The cerebellum. 3, 3, The spinal cord. 4, The
brachial plexus of nerves. 5, The lumbar plexus of nerves. 6, The
sacral plexus of nerves. 7, The facial nerve. 8, 17, The radial nerve.
9, 9, 16, The ulnar nerve. 10, The median nerve. G, The circumvex
nerve of the shoulder.

11, 11, The great sciatic nerve. 12, The external popliteal, or
peroneal nerve. 13, 13, The posterior tibial nerve. 14, Th