[Quantitative analysis of the bronchial tree structure in dogs and polar foxes]

Bronchial tree in the blue fox possesses a more complex structure that that of the dog and is characterized with a greater length and a greater number of generations in large and middle bronchi with a simultaneous decrease in the number of small bronchiole generations and a greater irregularity and asymmetry within segments. These peculiarities are connected with ecologically ensured in the North demands on increase of anatomically dead space.