Fig. 3. (A) Close up of the hilus of the lung of the ostrich Struthio camelus showing three medioventral secondary bronchi (filled circles) arising from the primary bronchus (p) (dissected out). Parabronchi, circled; a, pulmonary artery; v, pulmonary vein; n, cranial branch of the pulmonary artery. Each gradation on the scale bar, 1 cm. (B) A dental plastic impression at the hilus and the intrapulmonary primary bronchus (dashed line) showing the three medioventral secondary bronchi (filled circles). Parabronchi, circled; asterisk, a mediodorsal secondary bronchus. Each gradation on the scale bar, 1 cm.