Venkataramana Rao, J.

1. This is an appeal from the judgment of the learned Subordinate Judge of Rajahmundry granting a decree in favour of the plaintiff, the suit is upon a mortgage executed by the first defendant. The substantial defence to the suit was that the plaintiff was not entitled to ask for the sale of one of the items of the property, namely, Survey No. 172/2, on the ground that the property actually described in the deed of mortgage as having been mortgaged was only 172/4. The plaintiff in his plaint stated that the description 172/4 was a mistake for 172/2 and that if necessary the mortgage deed might be rectified by inserting 172/2 in the place of 172/4. But the substantial relief he prayed for in the plaint was the sale of 172/2 on the basis of the mortgage. One of the defences raised was that the prayer for rectification was barred by limitation because it was asked for after more than three years had elapsed from the date when the mistake came to the plaintiffs knowledge. This contention seems to have prevailed in the lower Court but the learned Subordinate Judge gave a decree on the ground that the prayer for rectification was an unnecessary prayer, that,