The figures following the specific names in the lists of mammals from each habitat indicate the number of individuals trapped, shot, or seen and positively identified in that habitat. NATURAL HABITATS _Aquatic habitat_: _Mustela vison mink._ Mink. Reported. _Fiber zibethicus zibethicus._ Muskrat. Reported. Mink and muskrat are reported by residents to occur in the Galien River in and near Warren Woods, but I was unable to secure any specimens though traps were set for them; neither did I see any signs of their presence. _Buttonbush-swamp habitat_: _Peromyscus leucopus noveboracensis._ Northern white-footed mouse. 8. _Mus musculus musculus._ House mouse. 2. A large buttonbush swamp occurs in the preserve just south of the Galien River, but around this the native trees have been cut away and over its accessible edges it has been heavily pastured, so that it is not at all in its natural conditions, and it was not trapped. In the unpastured flood-plain north of the river there is another buttonbush swamp of several hundred yards extent. This latter area was the one selected for study. In this typical swamp the buttonbush, _Cephalanthus occidentalis_, is practically the only plant present. It thickly covers the area with its tangled branches, which grow to heights of four to ten feet. The water had drained away in August, leaving the ground bare, though still wet and soft. Under the cover of the buttonbush there is no herbage whatever, and upon the ground there are only a few decaying logs and a few small sticks, which often carry a light growth of moss. Around the edges of this swamp there is a narrow belt of thick herbage, closely encroached upon by the typical forest of the flood-plain. Fifty mouse traps set in this habitat took eight northern white-footed mice and two house mice the first night, August 5. _Shore habitat_: _Procyon lotor lotor._ Raccoon. Tracks. _Peromyscus leucopus noveboracensis._ Northern white-footed mouse. 1. Along the shores of the Galien River a narrow strip of bare ground was exposed in July and August. The ground of this strip is mostly mud, but in a few places it is sand or gravel. Usually the habitat is narrow, but in some places it is five to ten feet wide. Tracks of raccoon were frequent on the shore along the river. From a few mouse traps set on the bare mud shore one northern white-footed mouse was taken August 4 beside a drift log. _Mud-bar herbage habitat_: _Peromyscus leucopus noveboracensis._ Northern white-footed mouse. 4.