Mo. R. Civ. P. 55.01
There shall be a petition and an answer; and there shall be a reply to a counterclaim denominated as such; an answer to a cross-claim, if the answer contains a cross-claim; a third-party petition, if a person who was not an original party is summoned under the provisions of Rule 52.11; and there shall be a third-party answer, if a third-party petition is served. A defense consisting of an affirmative avoidance to any matter alleged in a preceding pleading must be pleaded. No other pleading shall be required except as ordered by the court.
Mo. R. Civ. P. 55.01
Committee Note - 1974
This is substantially the same as prior Rule 55.01 with the addition of the second sentence to conform to Jaycox v. Brune 434 S.W.2d 539 (Mo.1968).
Compare: Rule 7(a) of the Federal Rules of Civil Procedure.