In an action for divorce on the ground of cruel and inhuman treatment, defendant appeals from so much of an order of the Supreme Court, Westchester County, dated March 8, 1979, as granted plaintiff's motion to strike paragraphs fourth through nineteenth of defendant's amended answer. Order affirmed insofar as appealed from, with $50 costs and disbursements. The subject paragraphs, although not labeled as such, can serve no purpose other than to constitute an affirmative defense. As such they were properly stricken because only statutory defenses are permitted in a matrimonial action, and there are no statutory defenses to an action for divorce on the ground of cruel and inhuman treatment (see Mante v. Mante, 34 A.D.2d 134; Biamonte v. Biamonte, 57 A.D.2d 1052). Furthermore, under the doctrine of "law of the case", Special Term was required to strike these paragraphs in view of defendant's failure to appeal from a prior order of another Judge of that court which had stricken the same allegations of the original answer. Lazer, J.P., Rabin, Shapiro and Margett, JJ., concur.