The " black mouse " or Carson field mouse (Microtus montanus) is found throughout Nevada, as well as in Utah, north-eastern California, and eastern Oregon; it multiplies rapidly under favourable conditions, and at times causes serious injury to crops.
There are several varieties of grasshopper mice (Orychomys), white-footed mice (Peromyscus), harvest mice (Reithrodontomys), rice-rats (Oryzomys), wood-rats (Neotoma), voles (Microtus), &c. Bats inhabit caves in Burnet, Williamson, Lampasas, Gillespie and other counties.
The peculiar odour evolved by many rodents is due to the secretions of special glands, which may open into the prepuce, as in Mus, Microtus and Cricetus, or into the rectum, as in Arctomys and Thryonomys, or into the passage common to both, as in the beaver, or into pouches opening near the vent, as in hares, agoutis and jerboas.
The first of these is the common shoa 1 tailed field-mouse, or "field-vole," Microtus agrestis, which belongs to the typical section of the type genus, and M S is about the size of a 343 mouse, with a short stumpy body, and a Upper and Lower Molars of the Water-Rat tail about one-third the (or Water-Vole), Microtus amphibius.
The second and larger species is the water-rat, or "watervole," which belongs to a second section of the genus, and is commonly known as Microtus (Arvicola) amphibius, although some writers employ the inappropriate specific name terrestris.