Sentence:  Also , interlobular air drifts may be all but nonexistent in the cow ; probably occur in the horse much as in the human being ; and , in contrast are present to a relatively immense degree on a segmental basis in the dog where <WSD>lobules</WSD> are absent ( Van Allen and Lindskog , ' 31 ) . 
Meaning of the word marked with <WSD> tags:  a small lobe or subdivision of a lobe