Abstract
Each lung of the domestic animals, exclusive of the horse, is divided intothe cranial, middle and caudal lobes with an addition of the accessory Robe in the rightlung. This lobation is in agreement with that described by Ellenberger and Baum (1932), but not with that mentioned by Seiferle (1956).The horse has the uniform left and right lungs divided into two lobes, as mentionedby Sisson and Grossman (1954). Regardless of the external difference, the left and rightlungs of the horse have those structures which correspond to the lobar bronchi and lobarblood vessels present in the lungs of the other domestic animals. There are, however, thefollowing differences: (l) The cranial and middle lobar bronchi in both lungs of the horseconstitute a common trunk, as is formed in the left lung of the other domestic animals, and (2) the caudal pulmonary vein in the right lung which is an unbranched vein in theother domestic animals is composed of cranial and caudal branches that enter the leftatrium.From a comparative anatomical point of view there are no fundamental differences inlobar bronchi and blood vessels between the unlobated lung of the horse and the lobatedlung of the other domestic animals.
