In November, 1894, one Jackson,' the plaintiff’s assignor, agreed to sell his saloon át No. 198 William street, in the city of New York, to the defendant, for $8,750, out of which sum there was to be allowed the amount due upon an existing mortgage of the fixtures made by Jackson to the Budweiser Brewing Company. ■ The sale was consummated by the delivery of a bill of sale and the transfer of the possession of the saloon *568to the defendant, and at the time the latter -deducted from the purchase money, firstly, $6,478, believed by both parties to be the amount of the mortgage debt alluded to, and; secondly, $250 retained under a special agreement then and there entered into whereby the defendant was to apply so much of such sum as was required to'discharge certain arrears of water rents, the amount of which had not been ascertained, and to pay the overplus, if any, to Jackson. The residue of the. purchase money .was paid, ■in cash and notes, since transferred to third persons, and also paid. The water rents subsequently proved to be but $110, and -the actual amount of the mortgage debt $6,782.50, which last-mentioned sum thé defendant paid by his own promissory notes to the Budweiser Brewing Company* secured by a new mortgage of the same fixtures, executed by him.

In this action by Jackson’s assignee to recover the overplus of .the sum retained by the defendant to satisfy the arrears of water rents, the latter sought to avail himself of the. sum paid by him in excess of the sum agreed to be paid upon the sale and purchase of the saloon, owing to the mistake with regard to the amount of the mortgage debt.

' The facts narrated above appear from uncontroverted evidence at the trial, and are not challenged upon this appeal. Indeed, the only grounds upon which the plaintiff’s counsel asks us to uphold the judgment in his client’s favor are that there was no proof of an assignment of the mortgage debt to the defendant, that the latter’s payment of such debt did not inure to Jackson’s benefit, and that non constat Jackson is not under a continuing liability to the Budweiser Brewing" Company therefor.

Obviously, the plaintiff’s counsel and the court below totally misapprehended the defendant’s claim. It was not that by subrogation or assignment he was entitled to demand and receive from the plaintiff’s assignor, .Jackson, any part of the latter’s indebtedness to the Budweiser Brewing Company, but that, owing to the mutual mistake of fact with regard to the amount of the mortgage debt, which at the time of the sale of the saloon was a lien upon the fixtures thereof, the plaintiff’s assignor had received from the defendant. $304.50, which ex aequo et bono he was bound to return at the time of his assignment of the overplus of the sum retained by the defendant to satisfy the.arrears of water rents. 18 Am. & Eng. Ency. of Law, 225, etc.; Keener’s Quasi Contracts, 26.

*569The sum paid by the defendant in excess of the agreed purchase money upon the sale of the saloon was recoverable by him in an action ex contractu, as for money had and received by the plaintiff’s assignor to his use (Roberts v. Ely, 113 N. Y. 128), and the cause of action was equally available to him as a counteirclaim- to the extent of the plaintiff’s demand. Code Civ. Pro., §§ 501, 502.

The judgment should be reversed and a new trial had, with costs to the appellant to abide the event.

Daly, P. J., and McAdam, J., concur.

Judgment reversed, and new trial ordered, with costs to appellant to abide event.