The ornamental design for urn having a seaurchinshape, as shown and described.
FIG. 1 is a top perspective view of an urn having a sea urchin shape according to the present invention.
FIG. 2 is a bottom perspective view of an urn having a sea urchin shape according to the present invention, wherein an interior perimeter of the opening is reduced to broken lines, and the broken lines form no part of the claimed design.
FIG. 3 is a front perspective view of an urn having a sea urchin shape according to the present invention.
FIG. 4 is a rear perspective view of an urn having a sea urchin shape according to the present invention.
FIG. 5 is a right side perspective view of an urn having a sea urchin shape according to the present invention; and,
FIG. 6 is a left side perspective view of an urn having a sea urchin shape according to the present invention.