_Overflow swamp habitat:_ Due to the rise in water-level of the lakes of the Cisco Lake chain many low areas of forest have been flooded and killed. Many of the dead trunks of these trees still remain standing, mixed with fallen and decaying logs in the water. Locally these habitats are called "overflow swamps," a name here adopted for the habitat. There is little living vegetation in these swamps, an occasional water lily being almost the only plant present. Porcupines commonly walk out on the logs of the swamp to secure the water lily leaves, and probably the mink occasionally runs over the logs in its movements along the waterways. _Cultivated-field habitat:_ Cleared fields occur only sparingly in the regions visited, and these fields are small in size. No study of their inhabitants was made, though silver-haired bats were collected while they were flying over a small clearing in the Little Girl's Point Region. _Edificarian habitat:_ Towns and buildings are not very common in northern Michigan. In and around a cabin on Lindsley Lake a number of deer-mice were trapped, and signs that porcupines had invaded the cabin were noted. ANNOTATED LIST OF MAMMALS _Condylura cristata._ Star-nosed Mole. Tall-sedge, 2. Two were trapped September 3 and 5, 1920, in a short, open runway in very moist soil at the edge of a small ditch running through tall sedges in a beaver meadow near Gogebic Lake, Ontonagon County. _Sorex personatus personatus._ Masked Shrew. Grassy-meadow, 2. Black spruce--tamarack bog, 2. Wet hardwood forest, 3. Dry hardwood forest, 3. Shrub stage, 2. In the Cisco Lake Region in July, one was taken in a small black spruce bog, two in a narrow tongue of grass between tall sedges and sphagnum bordering Mud Lake, three in the wetter parts of the hardwood forest, and three in the upland, well-drained hardwood forest. Near Little Girl's Point in August, two were taken in a growth of shrubs in a burn. Near Gogebic Lake, Ontonagon County, one was taken September 4 in a black spruce bog. _Sorex richardsonii._ Richardson Shrew. Tall-sedge, 15. Grassy-meadow, 1. Sphagnum bog, 1. This species was found only in or near tall sedges growing in moist or marshy situations. In the Cisco Lake Region six were taken near Mud Lake in July. Four of these were taken in tall sedges, one in grass alongside the sedges, and one in sphagnum between the sedges and the lake. August 30 to September 5, eleven were taken in tall sedges in a beaver meadow near Gogebic Lake, Ontonagon County. An adult female trapped at Mud Lake, July 30, contained five large embryos. There were two pairs of inguinal and one pair of abdominal mammae. Another adult female trapped in the same place, July 22, had two pairs of inguinal mammae, but no abdominal mammae were found.