_Remarks._--Intergradation occurs with _Dipodomys ordii chapmani_, _Dipodomys ordii longipes_, _Dipodomys ordii medius_ and _Dipodomys ordii attenuatus_. Only along the Rio Grande near El Paso, Texas, are individuals of a population uniform. On the periphery of the range, specimens from a given locality may resemble _D. o. ordii_ or _D. o. longipes_ or may be intermediate between these two subspecies. Animals from the Organ Mountains near Globe Springs, 20 miles north of Cliff, New Mexico, and those labeled with reference to Van Horn, Texas, on the average are darker, have a wider expanse across the auditory bullae, a wider interorbital region and, in most specimens, more distally flared nasals than the norm of other populations. This deviation from the normal is interpreted not as intergradation with any other subspecies but rather as individual variation in a given population. Specimens from 40 miles southeast of Corona and 10 miles northeast of Socorro, New Mexico, show intergradation between _D. o. ordii_ and _D. o. montanus_ in size of body, configuration of nasals and cranial size. For a discussion of intergradation with _D. o. longipes_, _D. o. medius_ and _D. o. chapmani_ see the remarks in the accounts of those subspecies. Specimens from Cananea and Santa Cruz, Sonora, Casas Grandes Viejo, Chihuahua City and Colonia Diaz, Chihuahua, are not typical of _D. o. ordii_ but rather show the influence of some race probably to the southeast that is as yet unknown. In a series of nine specimens from near Casas Grandes Viejo, Chihuahua, four individuals are typically _D. o. ordii_, four resemble an apparently undescribed form and one specimen is intermediate between _D. o. ordii_ and the unnamed subspecies. This unnamed race differs from _D. o. ordii_ in having darker pelage, darker dorsal stripe on tail, larger body, wider interorbital region, longer skull, greater breadth across the bullae, less vaulted braincase, more robust zygomatic arches and the foramen magnum more deeply notched on both the dorsal and ventral rims. It seems that these animals mentioned above should be referred to _D. o. ordii_ at least until such time as material becomes available from eastern Chihuahua, northern Coahuila and northeastern Durango. _Specimens examined._--Total, 451, distributed as follows: