The inner part of the dining room, designed for the table and couches, was often distinguished from the free space in the same way that the place for the bed was indicated in bedrooms, sometimes by a difference in the design of the mosaic floor, more frequently by the division of the wall decoration and the arrangement of the ceiling. In the third and fourth decorative styles the division is less plainly marked than in the second; but often the side walls back of the couches and the inner end of the room have each a single large panel with a small panel at the right and left, while on each side wall in front are only two panels, of the same size. In one respect the ordinary dining room was far from convenient; those who had the inner places could not leave the table or return to it in the course of a meal without disturbing one or more of those reclining nearer the outside. Large rooms, in which an open space was left between the couches and the wall, or in which several tables with their sets of couches could be placed, were unknown in pre-Roman Pompeii. In the time of the Empire a few of these large dining rooms were built in older houses. There is one measuring about 25 by 33 feet in the house of Pansa; another, of which the dimensions are 23 by 30 feet, in the house of Castor and Pollux; and a third, 36 feet long, in the house of the Citharist. In a number of houses we find a large, fine apartment--designated by the Greek word _oecus_--which seems often to have been used for a dining room, especially on notable occasions. A particularly elegant form was the Corinthian oecus, which had a row of columns about the sides a short distance from the walls, the room being thus divided into a main part with a vaulted ceiling and a corridor with a flat ceiling. The couches would be placed in the main part; the guests could pass to their places along the corridor, behind the columns. The remains of such an oecus may be seen in the houses of Meleager and of the Labyrinth. A specially interesting example--unfortunately not yet wholly excavated--is in the house of the Silver Wedding. In this case only the inner part, designed for the couches, is set off by columns. We may assume that there was a vaulted ceiling over the middle, resting on the entablature of the columns; that the ceiling of the corridor between the columns and the wall was flat, and of the same height as the entablature; and that the front part of the room had a flat or slightly arched ceiling of the same height as the crown of the vault over the middle.