Presently, he almost stumbles over what sent the musk-rat diving just at this place. It is the wreck of a wolverine's ravage--a little wattled dome-shaped house exposed to that arch-destroyer by the shrinking of the swamp. So shallow has the water become, that a wolverine has easily waded and leaped clear across to the roof of the musk-rat's house. A beaver-dam two feet thick cannot resist the onslaught of the wolverine's claws; how much less will this round nest of reeds and grass and mosses cemented together with soft clay? The roof has been torn from the domed house, leaving the inside bare and showing plainly the domestic economy of the musk-rat home, smooth round walls inside, a floor or gallery of sticks and grasses, where the family had lived in an air chamber above the water, rough walls below the water-line and two or three little openings that must have been safely under water before the swamp receded. Perhaps a mussel or lily bulb has been left in the deserted larder. From the oozy slime below the mid-floor to the topmost wall will not measure more than two or three feet. If the swamp had not dried here, the stupid little musk-rats that escaped the ravager's claws would probably have come back to the wrecked house, built up the torn roof, and gone on living in danger till another wolverine came. But a water doorway the musk-rat must have. That he has learned by countless assaults on his house-top, so when the marsh retreated the musk-rats abandoned their house. All about the deserted house are runways, tiny channels across oozy peninsulas and islands of the musk-rat's diminutive world such as a very small beaver might make. The trapper jumps across to a dry patch or mound in the midst of the slimy bottom and prods an earth bank with a stick. It is as he thought--hollow; a musk-rat burrow or gallery in the clay wall where the refugees from this house had scuttled from the wolverine. But now all is deserted. The water has shrunk--that was the danger signal to the musk-rat; and there had been a grand moving to a deeper part of the swamp. Perhaps, after all, this is a very old house not used since last winter. Going back to the bank, the trapper skirts through the crush of brittle rushes round the swamp. Coming sharply on deeper water, a dank, stagnant bayou, heavy with the smell of furry life, the trapper pushes aside the flags, peers out and sees what resembles a prairie-dog town on water--such a number of wattled houses that they had shut in the water as with a dam. Too many flags and willows lie over the colony for a glimpse of the tell-tale wriggling trail across the water; but from the wet tangle of grass and moss comes an oozy pattering.