=_Ondatra zibethicus osoyoosensis_= (Lord).--Muskrats were seen daily from June 17 to June 23 in a lake at locality 13. No specimen was obtained. =_Zapus princeps princeps_= J. A. Allen.--Nineteen Western Jumping Mice (60109-60126, 60137) were trapped at localities 6, 10, 12, 14, and 15. =_Erethizon dorsatum epixanthum_= Brandt.--A Porcupine skull was seen in the nest of a wood rat by John M. Legler at locality 3 on July 2. On June 20 a porcupine was seen at locality 12. No specimen was obtained. =_Mustela frenata nevadensis_= Hall.--Seven Long-tailed Weasels (60138-60143, 70152) were taken at localities 1, 4, 7, 8, 13, and 14. Four are males and three are females. Some of these were attracted by "squeaking" noises and then shot. =_Taxidea taxus taxus_= (Schreber).--One adult male Badger (60144) was found dead; the skull and baculum were saved. The subspecific identification is on geographic grounds, and is tentative. In this area _T. t. taxus_ and _T. t. fippsi_ may intergrade. =_Mephitis mephitis estor_= Merriam.--One Striped Skunk (60145) of unknown sex was found dead in the cellar of a cabin at locality 10. =_Odocoileus hemionus hemionus_= (Rafinesque).--Mule Deer were observed at locality 15; no specimen was obtained. DISCUSSION The species here reported from the Grand Mesa may be placed according to their geographic ranges and their restriction to certain habitats in two groups: BOREAL.--Each of the 12 species listed below is of northern distribution, is dependent, at the latitude of Colorado, upon the habitat provided by areas of high altitudes, and is near its southern zonal limit on the Grand Mesa. The 12 species are: _Sorex cinereus_, _Sorex palustris_, _Sorex vagrans_, _Ochotona princeps_, _Lepus americanus_, _Marmota flaviventris_, _Spermophilus lateralis_, _Clethrionomys gapperi_, _Phenacomys intermedius_, _Microtus longicaudus_, _Microtus montanus_, and _Zapus princeps_. _Thomomys talpoides_ may be considered in this category also, although it is less restricted in range and habitat than most of the other species listed as boreal. These thirteen species make up almost half of the twenty-seven species known from the Grand Mesa.