287.—Principal challenge. <A challenge of a juror for a cause which carries with it, prima facie, evident marks of suspicion either of malice or favor; as that a juror is of kin to either party within the ninth degree; that he has an interest in the cause, etc. 3 Bl. Comm. 363. A species of challenge to the array made on account of partiality or some default in the sheriff or his under-officer who arrayed the panel.