This is an action to recover back money had and received. Such an action, though legal in form, is in its nature an equitable remedy, and can only be main*552tained where the defendant has received money which, in equity and good conscience, he ought to pay to the plaintiff. Fay v. Lovejoy, 20 Wis. 407; Wells v. Am. Fxp. Co. 49 Wis. 224. The mere fact that the tax proceedings may have been irregular, and the amount of the tax has been paid under protest, will not authorize a recovery. Rutledge v. Price Co. 66 Wis. 35. The plaintiffs neither allege nor prove any defect or irregularity going to the validity of the assessment and affecting the groundwork of the tax, within the meaning of the statutes. Pier v. Prouty, 67 Wis. 218. They are therefore in no position to recover back a tax with which the property assessed was justly chargeable.

This action is prosecuted by executors. The judgment for costs is in form against them personally. Under the statute such judgment is unauthorized, unless the court therein expressly directs the same to be paid by such executors personally for mismanagement or bad faith in such action. Sec. 2932, R. S.; Ladd v. Anderson, 58 Wis. 591. The judgment should have contained a formal direction for the payment of the costs out of the estate. Hei v. Heller, 53 Wis. 415. For this manifest error the judgment of the circuit court is reversed, and the cause is remanded, with direction to reverse the judgment entered by the justice, and to enter judgment in accordance with this opinion.

By the Court.— Ordered accordingly.