The bronchial tree and lobular division of the lung of the white handed gibbon

The bronchial tree and lobular division of the lungs of four white handed gibbons (Hylobates agilis) were examined from the viewpoint of comparative anatomy, based upon the fundamental structure of the bronchial ramifications of the mammalian lung (Nakakuki, 1975, 1980). The right lung of the white handed gibbon consists of the upper, middle, lower, and accessory lobes, whereas the left lung consists of the middle and lower lobes. Each lobe is separated by the interlobular fissure, on both sides. The right and left lungs have the dorsal bronchiole system, lateral bronchiole system, and ventral bronchiole system. The medial bronchiole system is lacking on both sides. In the right lung, the upper lobe is formed by the first branch of the dorsal bronchiole system. The middle lobe is formed by the first brach of the lateral bronchiole system, and the accessory lobe by the first branch of the ventral bronchiole system. The remaining bronchioles constitute the right lower lobe. In the left lung, the upper lobe bronchiole, which is the first branch of the dorsal bronchiole system, is lacking. Therefore, the middle lobe bronchiole, i.e. the first branch of the lateral bronchiole system, is well developed. The accessory lobe bronchiole, the first branch of the ventral bronchiole system, is also lacking. The remaining bronchioles constitute the left lower lobe. These features were compared with those of other apes and man.