Sentence:  The country to be ridden over is selected the day before the run by the huntsman, who walks over the whole line with the <WSD>dragsman</WSD>, the legitimacy of the trail being assured by no mark of any kind being left on the line except on fences in which there is barbed wire. 
Meaning of the word marked with <WSD> tags:  One who lays down the scent trail for a hunt.