May 8, 1913, a nest containing six half-grown young was found by Kitt Cobb in marshy ground beside the Huron River at Portage Lake. The nest was in a good-sized cavity near the surface of the ground and was lined with dried grass. This species sometimes comes out on the surface of the ground, where I have found several individuals in early spring, most of them dead. February 10, 1907, near Ann Arbor, A. D. Tinker heard one tunneling in the snow and dug it out. _Sorex personatus._ Masked Shrew.--In this county the masked shrew is usually found in sphagnum and tamarack bogs. There are records for a tamarack bog, three miles south of Ann Arbor, and for Honey Creek, three miles west of Ann Arbor. I have found it mostly under old logs and in stumps in rather moist situations. _Blarina brevicauda talpoides._ Short-tailed Shrew.--Common in swamps, woodlands, and even in meadows, where it has its own runways and also uses those of the meadow mouse, on which it largely feeds. This shrew is diurnal as well as nocturnal, and I have often seen it in its runways. It is active all winter, and its tunnels may often be seen in the snow. While trapping in Steere's Swamp, south of Ann Arbor, a _Synaptomys cooperi_ in a trap was eaten by one of these shrews, which was later caught in the same trap. _Cryptotis parva._ Small Shrew.--The first record for the county was obtained in 1902 at Ann Arbor. In February, 1904, one was found in a barn three miles east of Ann Arbor. At Portage Lake, in 1916, a house cat brought two individuals to her kittens on October 29 and 31, respectively. The specimens taken by me were found in grassy places, usually where briers and shrubs were intermingled with the grass, but not in the woods. _Myotis lucifugus lucifugus._ Little Brown Bat.--Almost every winter individuals have been found in the building of the Museum of Zoology, at Ann Arbor, where they have been awakened by the heat long before insects were flying about. Max Peet took one at Ypsilanti June 6, 1904. _Myotis subulatus subulatus._ Say Bat.--In 1902 one was found alive in one of the buildings of the University of Michigan at Ann Arbor and was kept in a cage from February 26 to March 6, when it died. _Lasionycteris noctivagans._ Silver-haired Bat.--A female which seemed to have an injured wing was picked up at Ann Arbor by A. G. Ruthven, June 13, 1910. It contained two large embryos. This species is rare in this county. _Eptesicus fuscus fuscus._ Large Brown Bat.--Common at Ann Arbor and Ypsilanti. It is often found in buildings in winter. We have records for Ann Arbor every month except September, October, and November. Of all the bats this one is the most common about dwellings, and it is the one that most often enters houses at night in search of insects. Perhaps it is attracted by the light, as I have often seen it feeding about the street lights.