When they were nearly at close quarters, the light-armed troops in the van of each army began the combat, and here the Romans laboured under many disadvantages, the efficiency of the Carthaginians being much superior, since the Roman javelineers had had a hard time since daybreak, and had spent most of their missiles in the skirmish with the Numidians, while those they had left had been rendered useless by the continued wet weather. The cavalry and the whole army were in much the same state, whereas just the opposite was the case with the Carthaginians, who, standing in their ranks fresh and in first-rate condition, were ready to give efficient support wherever it was required. So when the skirmishers had retired through the gaps in their line and the heavy-armed infantry met, the Carthaginian cavalry at once pressed on both flanks of the enemy, being greatly superior in numbers and the condition of themselves and their horses, having, as I explained above, started quite fresh. When the Roman cavalry fell back and left the flanks of the infantry exposed, the Carthaginian pike-men and the Numidians in a body, dashing past their own troops that were in front of them, fell on the Romans from both flanks, damaging them severely and preventing them from dealing with the enemy in their front. The heavy-armed troops on both sides, who occupied the advanced centre of the whole formation, maintained for long a hand-to-hand combat with no advantage on either side.
Walbank Commentary