§334. It will be noticed from the plan (§330) that the _carcerēs_ were arranged in a curved line. This is supposed to have been drawn in such a way that every chariot, no matter which of the _carcerēs_ it happened to occupy, would have the same distance to travel in order to reach the beginning of the course proper at the nearer end of the _spīna_. There was no advantage in position, therefore, at the start, and places were assigned by lot. In later times a starting line (_līnea alba_) was drawn with chalk between the second _mēta_ and the seats to the right, but the line of _carcerēs_ remained curved as of old. At the ends of the row of chambers, towers were built which seem to have been the stands for the musicians; over the _porta pompae_ was the box of the chief official of the games (_dator lūdōrum_), and between his box and the towers were seats for his friends and persons connected with the games. In Fig. 142 is shown a victor pausing before the box of the _dator_ to receive a prize before riding in triumph around the arena. [Illustration: FIGURE 143.] §335. The Spina and Metae.--The _spīna_ divided the race course into two parts, making a minimum distance to be run. Its length was about two-thirds that of the arena, but it started only the width of the track from the _porta triumphālis_, leaving entirely free a much larger space at the end near the _porta pompae_. It was perfectly straight, but did not run precisely parallel to the rows of seats; at the end B in the exaggerated diagram (Fig. 143) the distance BC is somewhat greater than the distance AB, in order to allow more room at the starting line (_līnea alba_, §334), where the chariots would be side by side, than further along the course, where they would be strung out. The _mētae_, so named from their shape (§284), were pillars erected at the two ends of the _spīna_ and architecturally a part of it, though there may have been a space between. In Republican times the _spīna_ and the _mētae_ must have been made of wood and movable, in order to give free space for the shows of wild beasts and the exhibitions of cavalry that were originally given in the circus. After the amphitheater was devised the circus came to be used for races exclusively and the _spīna_ became permanent. It was built up, of most massive proportions, on foundations of indestructible concrete (§210 f.) and was adorned with magnificent works of art that must have entirely concealed horses and chariots when they passed to the other side of the arena. [Illustration: FIGURE 144. BOARD-GAME SHOWING SPINA] [Illustration: FIGURE 145. OBELISK ONCE IN CIRCUS MAXIMUS] [Illustration: FIGURE 146. A CANAL AS SPINA]