Section 30. If it appears in any proceedings under the seven preceding sections that an interest in such property is unrepresented by reason of a contingency or other cause by which the owner thereof is unknown or cannot then be ascertained, or because of the disability of such owner, a guardian ad litem to represent such interest may be appointed by the tribunal in which such proceedings are pending; or the judge of probate for the county in which such proceedings are pending may, upon petition of any party in interest, after such notice as he may order to all persons who, or whose issue unborn may be or may become interested in such apportionment, appoint a trustee, who, upon giving such bond as the judge of probate requires, shall represent such interest, and shall receive, manage and invest any money receivable on account thereof, for the benefit of the parties entitled thereto, and shall pay the principal and interest thereof to such parties when entitled thereto. Such guardian ad litem or trustee shall be allowed such costs, including counsel fees, as may be ordered by the court in which such proceedings are finally determined, to be paid from the damages apportioned to the interest which he represents.