In what circumstances will a defendant waive the statute of limitations defense?

In the absence of exceptions not applicable here, "the statute of limitations is a personal privilege which `. . . must be affirmatively invoked in the lower court by appropriate pleading . . .' or else it `is waived.'" (Mysel v. Gross (1977) 70 Cal.App.3d Supp. 10, 15.) There are two ways of pleading the defense: One is to allege the cause of action is barred by a specific code section; the other is to state underlying facts, (in this instance, the contractual provision) demonstrating the action is barred and indicating the lateness establishes the bar. (Ibid.) Defendant did neither, waiving the defense as a matter of law. The court properly denied the motion for directed verdict.