§ 389. Any person interested may appear and defend. Any person
interested in the property, or whose interests may be affected by the
final order or judgment of registration in the proceeding, whether
specifically named in the notice or not, may enter his appearance by
serving a copy of the same on the registrar of the county in which the
property is located and with the clerk of the supreme court in such
county, and filing the original thereof together with proof of service
with the county clerk on or before the return day or within such further
time as may be allowed by the court; and may enter his objections, if
any, by likewise serving a copy of the same on the registrar of the
county in which the property is located and with the clerk of the
supreme court in such county, and filing the original thereof together
with proof of service with the county clerk on or before the return day
or within such further time as may be allowed by the court; and may
oppose the petition for registration of the property as belonging to the
petitioner, or set up a cross-demand to have the title registered in his
own behalf. In any case, he shall state particularly what his interest
is and shall specifically state all objections to the petition.