Note the large _aorta_ given off from the left ventricle. Note the two large branches, the _innominate arteries_, given off by it near its origin. Each innominate divides into three smaller arteries, a _carotid_, _branchial_, and _pectoral_. The aorta itself turns toward the back and continues posteriorly through the body as the _dorsal aorta_. To the right auricle come three large veins, the _right_ and _left præcavæ_ and the _postcava_. Each præcava is formed by three veins, the _jugular_ from the head, the _branchial_ from the wing, and the _pectoral_ from the pectoral muscles. The postcava comes from the liver. From the right ventricle go the short _right_ and _left pulmonary arteries_ to the lungs, and from the lungs the blood is brought to the left auricle through the _right_ and _left pulmonary veins_. TECHNICAL NOTE.--For a detailed study of the circulation of the bird the teacher should inject the blood system of some larger bird, as a pigeon or fowl, for a class-demonstration. (For a guide, use Parker's "Zootomy," p. 209, or Martin and Moale's "How to Dissect a Bird," pp. 135-140 and pp. 148, 149.) In the posterior dorsal region of the body-cavity will be found large three-lobed organs fitting into the spaces between the bones of the back on either side. These are the _kidneys_, and from their outer margins on each side a _ureter_ runs posteriorly into the cloaca. Overlying the anterior ends of the kidneys are the reproductive organs. In the male these glands consist of firm, whitish, glandular bodies. From each runs a long convoluted _vas deferens_, which enters the cloaca. This tube corresponds to the _egg-duct_ of the female. In the female the _right egg-gland_ and _egg-duct_ or _oviduct_ are wanting. The _left egg-gland_ appears as a glandular mass; during the breeding season yellow _ova_ or _eggs_ in various stages of development project from its surface. The oviduct opens by a funnel-shaped mouth near the _egg-gland_ and runs thence to the cloaca. The eggs pass from the egg-gland into the body-cavity, where they are caught in the upper end of the oviduct and carried down and out through the cloacal opening. It is in the oviduct that the egg derives its accessory covering, which consists of a white or albuminous portion, together with several enveloping membranes and the hard shell enclosing all. Remove the top of the skull and note the large _brain_. What portions of the brain make up the greater part of it? Note the differences between this brain and that of the toad. Trace the principal _cranial nerves_. Work out the _spinal cord_ and principal _spinal nerves_. For an account of the nervous system of the sparrow see Martin and Moale's "How to Dissect a Bird," pp. 150-163. TECHNICAL NOTE.--For a study of the skeleton of the sparrow a specimen should be cleaned by boiling in a soap-solution (see p. 452). [Illustration: FIG. 132.--Dissection of the English sparrow, _Passer domesticus_.]