1934) 155) and which allow an amendment of pleadings to conform to the evidence, where the adverse party has not been misled and prejudiced (e.g., N.M.Stat.Ann. (Courtright, 1929) 105 -- 601, 105 -- 602). Under the amendment the court has discretion to permit a supplemental pleading despite the fact that the original pleading is defective. As in other situations where a supplemental pleading is offered, the court is to determine in the light of the particular circumstances whether filing should be permitted, and if so, upon what terms. The amendment does not attempt to deal with such questions as the relation of the statute of limitations to supplemental pleadings, the operation of the doctrine of laches, or the availability of other defenses. All these questions are for decision in accordance with the principles applicable to supplemental pleadings generally. Cf. Blau v. Lamb , 191 F.Supp. 906 (S.D.N.Y. 1961); Lendonsol Amusement Corp. v. B. & Q. Assoc., Inc ., 23 F.R.Serv. 15d. 3, Case 1 (D.Mass. 1957). Notes of Advisory Committee on Rules -- 1966 Amendment Rule 15(c) is amplified to state more clearly when an amendment of a pleading changing the party against whom a claim is asserted (including an amendment to correct a misnomer or misdescription of a defendant) shall "relate back" to the date of the original pleading. The problem has arisen most acutely in certain actions by private parties against officers or agencies of the United States. Thus an individual denied social security benefits by the Secretary