Diagrammatic longitudinal section of the body. Labels: a, the neural tube, with its upper enlargement in the skull cavity at a'; N, the spinal cord; N', the brain; ee, vertebrae forming the solid partition between the dorsal and ventral cavities; b, the pleural, and c, the abdominal division of the ventral cavity, separated from one another by the diaphragm, d; i, the nasal, and o, the mouth chamber, opening behind into the pharynx, from which one tube leads to the lungs, l, and another to the stomach, f; h, the heart; k, a kidney; s, the sympathetic nervous chain. From the stomach, f, the intestinal tube leads through the abdominal cavity to the posterior opening of the alimentary canal.

Longitudinal Section of Body

Diagrammatic longitudinal section of the body. Labels: a, the neural tube, with its upper enlargement…