18. Effect of registration of marriage under this Chapter. - Subject to the provisions contained in sub-section (2) of section 24, where a certificate of marriage has been finally entered in the Marriage Certificate Book under the Chapter, the marriage solemnized under this Act, and all children born after the date of the ceremony of marriage (Whose names shall also be entered n the Marriage Certificate Book) shall in all respects be deemed to be and always to have been the legitimate children of their parents: Provided that nothing contained in this section shall be construed as conferring upon any such children any rights in or to the property of any person other than their parents in any case where, but for the passing of this Act, such children would have been incapable of possessing or acquiring any such rights by reason of their not being the legitimate children of their parents.