A moment later his head and shoulders appeared above the top of the dam. Scarce an arm's length away Broken Tooth was forcing into place a three-foot length of poplar as big around as a man's arm. He was so busy that he did not hear or see Kazan. Another beaver gave the warning as he plunged into the pond. Broken Tooth looked up, and his eyes met Kazan's bared fangs. There was no time to turn. He threw himself back, but it was a moment too late. Kazan was upon him. His long fangs sank deep into Broken Tooth's neck. But the old beaver had thrown himself enough back to make Kazan lose his footing. At the same moment his chisel-like teeth got a firm hold of the loose skin at Kazan's throat. Thus clinched, with Kazan's long teeth buried almost to the beaver's jugular, they plunged down into the deep water of the pond. Broken Tooth weighed sixty pounds. The instant he struck the water he was in his element, and holding tenaciously to the grip he had obtained on Kazan's neck he sank like a chunk of iron. Kazan was pulled completely under. The water rushed into his mouth, his ears, eyes and nose. He was blinded, and his senses were a roaring tumult. But instead of struggling to free himself he held his breath and buried his teeth deeper. They touched the soft bottom and for a moment floundered in the mud. Then Kazan loosened his hold. He was fighting for his own life now--and not for Broken Tooth's. With all of the strength of his powerful limbs he struggled to break loose--to rise to the surface, to fresh air, to life. He clamped his jaws shut, knowing that to breathe was to die. On land he could have freed himself from Broken Tooth's hold without an effort. But under water the old beaver's grip was more deadly than would have been the fangs of a lynx ashore. There was a sudden swirl of water as a second beaver circled close about the struggling pair. Had he closed in with Broken Tooth, Kazan's struggles would quickly have ceased.