3. The pulmo-cutaneous arch gives off:—
(a) A pulmonary artery, running along the outer side of the whole length of the lung.
(b) A cutaneous artery, which at first runs forwards and upwards, and then turns backwards, supplying the skin of the back and the sides of the head.]
Make a complete sketch of the arterial system.
Fig. 7.—Arterial System of Xenopus and Rana.
Cut out the heart, leaving attached to it as much as possible of the large vessels.
Note the sinus venosus, truncus arteriosus, auricles, and ventricle.
Open the auricles and observe the division between them and the openings of the veins passing into them.
Make a section through the auricles and ventricle noting the thick muscular walls of the ventricle and the valves between it and the auricles.