Bending my ear close to the nearest lodge I rapped sharply on the rough wall and listened. There was no sound. Again I rapped and my knock was all that disturbed the silence within. Outside the frozen marsh grasses sawed silkily one on another and the frost crystals that the wind was sweeping from the thick white ice shrilled infinitesimally as they slid by, but no sound came from the lodge. Evidently no one was at home. At the next lodge it was different. The rap was succeeded by a second of breathless silence, then there was the sound of scrambling, and as I watched the dark clear ice that always obtains just about the lodge I saw three silver gleams shoot athwart the clear space and vanish under the opaque ice just beyond. Three Mussascuses had fled, their dense, dark, close-set under fur holding the air entangled in its fine fuzz which is impervious to water, thus accounting for the gleam. Like the fur-seal the muskrat has an outer coat of rather coarse hair and an undervest of much finer, more silky texture. This provides an air space which enfolds him, however long he remains under water, and its chill may not reach him nor can the moisture. Only the soles of his feet and the very tip of his muffle, the nose-pad, are bare. His ears are set down within his fur, and when he is beneath the surface each holds an earful of air that catches under-water sounds and transmits them as faithfully as it does the sounds of the upper world. He swims by vigorous “dog-paddle” motions of his hind feet, which are large and furnished with stiff, coarse hair that answers for a webbing between the toes. Moreover, these feet are “hung-in” a little in a peculiar club-footed way that makes his gait on land an awkward shamble, but which allows them to “feather” as an oar does in swimming, thus giving his propulsive apparatus the greatest possible efficiency. People who know Mussascus best differ about the use of his tail. I have never seen him use it except as a very efficient steering oar, but I have been told that he sculls with it as a fish does with his, and thus helps his progress. It is admirably adapted for either purpose, but it is a tail that does not look as if it belonged to any fur-bearing animal. It is almost as long as the muskrat himself and has never a hair from butt to tip. Instead, it is furnished with small stiff scales which might just as well be those of a snake. It is flattened sidewise and trimmed down to almost a knife-edge at top and bottom, and the muskrat uses it most efficiently.