The moon at this moment shining more brilliantly, enabled him to command a better view of the waters of the lake, and the selvage of reeds growing around it. Once more silence was reigning over the scene, when all at once Don Cornelio fancied he saw a movement among the sedge, as if some one was making his way through it. In another instant a form, at first shadowy and indistinct, appeared before his eyes. Presently it assumed the outlines of a human form, and what astonished Don Cornelio still more, it was the form of a woman! This he saw distinctly; and perceived also that the woman was dressed in a sort of white garment, with long dark hair hanging in disordered tresses over her shoulders. A cold perspiration broke out upon the brow of Don Cornelio, as the female form was recognised; and his eyes became fixed upon it, without his having the power to take them off. He doubted not that he saw before him the companion of Tlaloc, the terrible Matlacuezc, who had just risen from her watery palace in the Lake Ostuta, whence she had been summoned by the invocations of Costal, the descendant of the ancient rulers of Tehuantepec! CHAPTER SEVENTY SIX. TOLLING THE SUMMONS. We return to Costal. We have seen the Zapoteque making his way through the sedge, and boldly launching himself into the muddy waters of the lake--his blind fatalism rendering him regardless of the voracious alligators of the Ostuta, as he had already shown himself of the sharks of the Pacific. Could the eye of Don Cornelio have followed him under the gloomy shadow which the enchanted hill projected over the lake, it would have seen him emerge from the water upon the shore of the sacred Cerro itself, his black-skinned associate closely following at his heels. The mountain Monopostiac is neither more nor less than a gigantic rock of obsidian, of a dark greenish hue, having its flanks irregularly furrowed by vertical fissures and ridges. This peculiar kind of rock, under the sun, or in a very bright moonlight, gives forth a sort of dull translucence, resembling the reflection of glass. The vitreous glistening of its sides, taken in conjunction with the mass of thick white fog which usually robes the summit of the mountain, offers to the eye an aspect at once fantastic and melancholy. At certain places, of which Costal had a perfect knowledge, are huge boulders of obsidian, resting along the declivities of the Cerro, and which, when struck by a hard substance, gives forth a sonorous ring, having some resemblance to the sound of a bell. After climbing some way up the steep declivity of the mountain, Costal and his neophyte halted by one of these boulders. Now apparently absorbed in profound meditation, now muttering in a low tone, and in the language of his fathers, certain prayers, the Zapoteque awaited that hour when the moon should reach its meridian, in order to come to the grand crisis of his invocation.