The Pantheon is an exception, since the dome has an open eye; and one great ornament of this beautiful structure is in the arrangement of internal columns placed in the front of niches, composed of antae, or pier-formed ends of walls, to carry an entablature round under an attic on which the cupola rests.

Another characteristic feature of the early oratory is seen in the curious antae or prolongation of the side walls.

It consists of four columns and two antae, of the Grecian Ionic order, supporting an entablature and pediment, and forming together one grand portico.

To give the requisite elevation, the columns and antae are raised upon pedestals; these, as well as the basement story and podium of the inner wall of the portico, are of Aberdeen granite; the columns and the rest of the front are formed of large blocks of Portland stone.

It will have a portico of two columns, and two antae of Portland stone, of the height of the ground story, which is very lofty, and the width of the entire compartment of the front.