+THOLOS OF ATREUS.+ All these structures present, however, only the rudiments of architectural art. The so-called +Tholos+ (or Treasury) of +Atreus+, at Mycenæ, on the other hand, shows the germs of truly artistic design (Fig. 24). It is in reality a tomb, and is one of a large class of prehistoric tombs found in almost every part of the globe, consisting of a circular stone-walled and stone-roofed chamber buried under a tumulus of earth. This one is a beehive-shaped construction of horizontal courses of masonry, with a stone-walled passage, the _dromos_, leading to the entrance door. Though internally of domical form, its construction with horizontal beds in the masonry proves that the idea of the true dome with the beds of each course pitched at an angle always normal to the curve of the vault, was not yet grasped. A small sepulchral chamber opens from the great one, by a door with the customary relieving triangle over it. [Illustration: FIG. 24.--THOLOS OF ATREUS. PLAN AND SECTION.] [Illustration: FIG. 25.--THOLOS OF ATREUS. DOORWAY.] Traces of a metal lining have been found on the inner surface of the dome and on the jambs of the entrance door. This entrance is the most artistic and elaborate part of the edifice (Fig. 25). The main opening is enclosed in a three-banded frame, and was once flanked by columns which, as shown by fragments still existing and by marks on either side the door, tapered downward as in the sculptured column over the Lion Gate. Shafts, bases, and capitals were covered with zig-zag bands or chevrons of fine spirals. This well-studied decoration, the banded jambs, and the curiously inverted columns (of which several other examples exist in or near Mycenæ), all point to a fairly developed art, derived partly from Egyptian and partly from Asiatic sources. That Egyptian influences had affected this early art is further proved by a fragment of carved and painted ornament on a ceiling in Orchomenos, imitating with remarkable closeness certain ceiling decorations in Egyptian tombs.