mi. W Casas Grandes Viejo, 1 (MVZ); Casas Grandes, 2 (USBS);

Gallego, 1 (USBS); Colonia Diaz, 6 (USBS); Las Trincheras, 9 mi. S by road Boquillos de Condios, 4 (MVZ); Santa Rosalia, 6 (USBS); Chihuahua, 7 (USBS); 5 mi. SE Chihuahua, 5250 ft., 4 (MVZ); Corallitos, 4 (1 USBS; 3 MVZ).

=Dipodomys ordii luteolus= (Goldman)

_Perodipus ordii luteolus_ Goldman, Proc. Biol. Soc. Washington, 30:112, May 23, 1917.

_Dipodomys phillipsi ordi_, Coues and Allen, Monogr. of N. Amer. Rodentia, p. 541, August, 1877 (part--the part from Niobrara River, Nebraska).

_Perodipus montanus richardsoni_, Cary, N. Amer. Fauna, 33:141, August 17, 1911 (part--the part from Sterling, Colorado).

_Dipodomys ordii luteolus_, Grinnell, Journ. Mamm., 2:96, May 2, 1921.

_Type._--Male, adult, no. 160408, U. S. Nat. Mus. Biol. Surv. Coll.; Casper, Natrona County, Wyoming; obtained on September 2, 1909, by Merritt Cary, original no. 1690.

_Range._--Southeastern Wyoming, northeastern Colorado, northwestern half of Nebraska and southwestern South Dakota; marginal occurrences are: in Wyoming, Casper, Sun and Ft. Steele; in Colorado, Loveland, Hugo and Akron; in Nebraska, Birdwood Creek, Neligh and Valentine; in South Dakota, Batesland and Buffalo Gap.

_Diagnosis._--Size medium (see measurements). Color light, entire dorsal surface between Light Ochraceous-Buff and Ochraceous-Buff, purest on sides and flanks; upper parts but lightly washed with black; arietiform markings, plantar surfaces of hind feet, pinnae of ears and dorsal and ventral stripes of tail, blackish. Skull medium in size; jugal weak; braincase slightly inflated; nasals slightly flared distally.

_Comparisons._--From _Dipodomys ordii terrosus_, _D. o. luteolus_ differs as follows: Size smaller, except that tail and ear are longer; color lighter in all pigmented areas; skull smaller in every measurement taken; auditory bullae less inflated; zygomatic processes of maxillae smaller; cutting edge of upper incisors narrower; zygomatic arch weaker.

From _Dipodomys ordii priscus_, _D. o. luteolus_ differs in: Size larger except hind foot which is shorter; dorsal and ventral stripes of tail, plantar surfaces of hind feet, arietiform markings and pinnae of ears, in most specimens, darker; auditory bullae less inflated; nasals shorter; rostrum wider; total length of skull shorter; zygomatic arch weaker; foramen magnum more ovate.

From _Dipodomys ordii evexus_, _D. o. luteolus_ differs as follows: Hind foot longer; color lighter in all pigmented areas; auditory bullae more inflated; pterygoid fossae more expanded laterally; width across maxillary arches less; interorbital region narrower; zygomatic arch weaker; external auditory meatus almost round as opposed to ovoid.

Comparison with _Dipodomys ordii richardsoni_ is made in account of that subspecies.

_Remarks._--_Dipodomys ordii luteolus_ resembles _D. o. priscus_ in size and color but can readily be told from it and _D. o. richardsoni_ when specimens from the central portions of the ranges of the subspecies are compared. At and near the periphery of the range, especially in that part which adjoins the range of _D. o. richardsoni_, intergradation occurs. Specimens from Kennedy, Perch and Neligh, Nebraska, approach _D. o. richardsoni_ in the shape of the pterygoid fossae and nasal bones, but in all other characters they resemble _D. o. luteolus_ to which subspecies they are here referred. Specimens from Loveland and 20 miles east of Avalo, Colorado, show intergradation with _D. o. richardsoni_ in the width of the rostrum and size of the zygomatic arch but are referable to _D. o. luteolus_.

No specimens here referred to _D. o. luteolus_ were found to intergrade with _D. o. priscus_.

_Specimens examined._--Total, 250, distributed as follows:

=South Dakota=: _Perkins County_: 9 mi. N Bison, 8 (MVZ). _Meade County_: Smithsville, 2 (USBS). _Jackson County_: 20 mi. SSE Phillip, in Haakon County, 1 (MVZ). _Custer County_: Elk Mountain, 1 (MHS); Buffalo Gap, 2 (USNM). _Bennett County_: Big Spring Canyon, Batesland, 7 (CNHM); Rosebud Indian Agency, 1 (USBS).

=Wyoming=: _Fremont County_: 2-1/2 mi. W Shoshoni, 80 (KU); Granite Mountain, 1 (UM). _Natrona County_: 1 mi. NE Casper, 19 (KU); Casper, 7 (USBS); Sun, 8 (USBS). _Converse County_: Douglas, 2 (USBS). _Niobrara County_: Van Tassel Creek, 1 (CM). _Carbon County_: Fort Steele, 1 (USBS). _Goshen County_: Rawhide Butte, 1 (USBS).

=Nebraska=: _Sioux County_: Warbonnet Canyon, 6 (MHS); Glen, 1 (MHS); Agate, 3 (1 UM; 2 CNHM); Jim Creek, 1 (MHS). _Box Butte County_: 16 mi. NE Alliance, 4 (UM). _Sheridan County_: 12 mi. S Gordon, 3 (MVZ); 5 mi. N Antioch, 4 (UM); 4 mi. N Antioch, 3 (UM). _Cherry County_: Valentine, 9 (6 USBS; 2 USNM; 1 NU); 15 mi. E Gordon, 1 (CNHM); Niobrara River, 3 (USBS); 18 mi. NW Kennedy, 3 (2 USBS; 1 MHS); Valentine Lake Refuge, 1 (NU); Kennedy, 10 (3 MVZ; 5 USBS; 2 USNM); 30 mi. S Wood Lake, 4 (CNHM); Cherry, 7 (NU); near Clark's Canyon, 7 (USBS). _Rock County_: Perch, 12 (10 AMNH; 2 CNHM). _Antelope County_: Neligh, 8 (1 USBS; 7 MHS). _Scotts Bluff County_: Mitchell, 1 (MHS). _Hooker County_: Kelso, 5 (UM). _Thomas County_: Halsey, 1 (MHS); Dismal River, 2 (USBS). _Custer County_: 1 mi. NW Gavin, 6 (2 MVZ; 4 UM); Gavin, 3 (UM); 8 mi. NW Anselmo, 1 (UM); 7 mi. NW Anselmo, 1 (UM). _Lincoln County_: Birdwood Creek, 2 (USBS); Brady, 4 (NU); Hackberry Lake, 13 (UM).

=Colorado=: _Larimer County_: Loveland, 8 (USBS). _Weld County_: 20 mi. E Avalo, 3 (USBS); 8 mi. E Pawnee Buttes, 1 (USBS); Greeley, 1 (USBS). _Morgan County_: 30 mi. S Fort Morgan, 1 (UM). _Logan County_: Sterling, 8 (USBS). _Adams County_: Barr Lake, 4 (CMNH); 6 mi. E and 1 mi. N Denver, 1 (CMNH); 3 mi. NE Fitzsimons, 1 (CMNH). _Washington County_: Akron, 2 (UM). _Lincoln County_: Limon, 1 (USBS); Hugo, 1 (USBS). _El Paso County_: Colorado Springs, 2 (MVZ).

=Dipodomys ordii extractus= new subspecies

_Type._--Male, adult, no. 76562, Museum of Vertebrate Zoology, University of California; 1 mi. E Samalayuca, 4500 ft., Chihuahua, Mexico; obtained on May 15, 1937, by William B. Richardson, original no. 2148.

_Range._--Known only from the type locality.

_Diagnosis._--Size medium (see measurements). Color pale, entire dorsal surface Pinkish Buff, purest on sides and flanks, dorsal surface but slightly suffused with black; pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail light-brownish. Skull medium in size; nasals long; rostrum relatively as well as actually wide; least interorbital breadth wide; auditory bullae relatively little inflated; braincase but slightly vaulted; external auditory meatus ovoid; zygomatic arches relatively robust and but slightly bowed laterad; pterygoid fossae subcircular; lacrimal processes small; foramen magnum deeply notched on dorsal border.

_Comparisons._--From _Dipodomys ordii ordii_, _D. o. extractus_ differs as follows: Size larger; color lighter; arietiform marks absent in _D. o. extractus_ but pronounced in _D. o. ordii_; skull larger; rostrum wider; nasals longer; re inflated laterally; braincase less vaulted; pterygoid fossae subcircular as opposed to circular; foramen magnum more deeply evaginated dorsally and ventrally.

From _Dipodomys ordii obscurus_, _D. o. extractus_ differs as follows: Size larger; color lighter; skull larger in all respects, notably in least interorbital width, greatest length of skull and breadth across auditory bullae; zygomatic arches less robust and straight as opposed to robust and bowed laterally; pterygoid fossae subcircular as opposed to circular; auditory bullae more inflated ventrally.

From _Dipodomys ordii idoneus_, _D. o. extractus_ differs in: Size larger; color lighter; skull larger in all measurements taken except least interorbital width and breadth across maxillary arches which are smaller; nasals longer and narrower; braincase less vaulted; zygomatic arches less robust and more nearly straight; auditory bullae less inflated ventrally.

_Remarks._--This subspecies of _Dipodomys ordii_ is the palest of any of the known races from Mexico. It inhabits an area of light-colored sandy soil at the type locality.

The only subspecies with which _D. o. extractus_ really needs comparison is _Dipodomys ordii ordii_ from which it differs as described above. The series which is herein described contains two individuals that resemble _D. o. ordii_ cranially and three that resemble it in color although they are somewhat paler. One specimen, MVZ no. 76560, is the palest of any of the series, has a short tail and in these respects resembles the pale form of _Dipodomys ordii compactus_. It is apparent from the skull of this latter individual that it is not _D. o. compactus_ but _D. o. extractus_.

_Dipodomys ordii ordii_ inhabits, in most of its range, dark-colored soils, whereas _D. o. extractus_ inhabits light-colored soils. Possibly the differentiation that has occurred is a result of an ecological separation much as occurs with _Perognathus_ on the white sands and black lavas of the Tularosa Basin of New Mexico (see Benson, 1933).

_Specimens examined._--Total, 14, all from Chihuahua, as follows: 1 mi. E Samalayuca, 4500 ft., 14 (MVZ).

=Dipodomys ordii chapmani= Mearns

_Dipodomys chapmani_ Mearns, Bull. Amer. Mus. Nat. Hist., 2:291, February 21, 1890.

_Cricetodipus chapmani_, Trouessart, Catalogus Mammalium, 1:581, 1897.

_Perodipus chapmani_, Elliot, Field Columbian Museum, Zool. Ser., 2:237, 1901.

_Perodipus ordii chapmani_, Goldman, Proc. Biol. Soc. Washington, 30:113, May 23, 1917.

_Dipodomys ordii chapmani_, Grinnell, Journ. Mamm., 2:96, May 2, 1921.

_Cotypes._--Male, no. 2400, and female, no. 2398, Amer. Mus. Nat. Hist.; Fort Verde, Yavapai County, Arizona; obtained on January 26, 1887, and October 1, 1885, respectively, by Edgar A. Mearns. (Type not seen.)

_Range._--Central Arizona from the Grand Canyon of the Colorado River, southeastward to, and probably beyond, Fort Verde; marginal occurrences are: lower end Prespect Valley, Kirkland, Prescott, Camp Verde, Bill Williams Mountain.

_Diagnosis._--Size medium (see measurements). Color dark; entire dorsal surface between (_10''_) Pinkish Cinnamon and Cinnamon-Buff, purest on sides and flanks, upper parts strongly suffused with black; arietiform markings, pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail, blackish. Skull medium in size; rostrum long and narrow; nasals long; auditory bullae slightly distended; braincase vaulted.

_Comparisons._--For comparisons with _Dipodomys ordii cupidineus_, _Dipodomys ordii longipes_ and _Dipodomys ordii ordii_ see accounts of those subspecies.

_Remarks._--This subspecies of _Dipodomys ordii_ is relatively isolated from other subspecies of the species. The Colorado River with its deep canyons is interposed between the ranges of _D. o. chapmani_ and _D. o. cupidineus_. A high range of mountains separates _D. o. chapmani_ from the range of _D. o. longipes_. The only race with which _D. o. chapmani_ probably comes into contact is _D. o. ordii_ to the southeast. No specimens are available from the southeastern part of the range of _D. o. chapmani_. Animals from the northwestern part of the range of _D. o. ordii_, without exception, have dark-colored pelage which is characteristic of _D. o. chapmani_. In the shape of the nasals, vault of the braincase, interorbital width and auditory bullae, animals from Rice, Arizona, resemble _D. o. chapmani_, but in other characters resemble _D. o. ordii_ to which subspecies they are referred. Animals from 20 miles northeast of Calva, Arizona, are dark-colored and are intermediate between the dark _D. o. chapmani_ and the pale _D. o. ordii_ in size of the cranium and body but are referable to _D. o. ordii_. In the northwestern part of the range of _D. o. chapmani_ the animals are not typical in that they have a shorter, wider rostrum and a heavier zygomatic arch than topotypes.

_Specimens examined._--Total, 90, all from Arizona, distributed as follows: _Mohave County_: lower end Prospect Valley, 4500 ft., Grand Canyon, 7 (USBS); Kingman, 9 (LACM). _Coconino County_: Aubrey Valley, 10 mi. S Pine Spring, 4 (USBS); Bill Williams Mountain, 1 (USNM). _Yavapai County_: 3 mi. N Fort Whipple, 11 (USBS); Fort Whipple, 4 (2 USBS; 2 USNM); Willow Creek, 4 mi. N Prescott, 4 (MVZ); 1 mi. W Camp Verde, 1 (MVZ); Camp Verde, 33 (15 USBS; 3 MVZ; 3 AMNH; 9 LACM; 3 DRD); 1/2 mi. S Camp Verde, 4 (MVZ); Kirkland, 9 (USBS); Turkey Creek, 3 (USBS).

=Dipodomys ordii montanus= Baird

_Dipodomys montanus_ Baird, Proc. Acad. Nat. Sci. Philadelphia, 7:334, April, 1855.

_Perodipus montanus_, Merriam, Proc. Biol. Soc. Washington, 17:140, July 14, 1904.

_Perodipus ordii montanus_, Goldman, Proc. Biol. Soc. Washington, 30:113, May 23, 1917.

_Dipodomys ordii montanus_, Grinnell, Journ. Mamm., 2:96, May 2, 1921.

_Type._--Male, no. 490/1631, U. S. Nat. Mus.; near Fort Massachusetts, Costilla County, Colorado; obtained in 1853 by F. Kreutzfeldt (Pacific Railroad Survey).

_Range._--The San Luis Valley of south-central Colorado and north-central New Mexico; marginal occurrence are: in Colorado, 22 mi. E Mosca, Saguache, Alamosa and Antonito; in New Mexico, 4 mi. SW Cimmaron.

_Diagnosis._--Size small (see measurements). Color dark, entire dorsal surface between (_c_) Vinaceous-Buff and Avellaneous, purest on sides and flanks, upper parts strongly suffused with black; arietiform markings, pinnae of ears, plantar surfaces of hind feet and dorsal and ventral stripes of tail, blackish. Skull small; rostrum slender; interorbital width narrow; auditory bullae strongly inflated; braincase but slightly vaulted; interparietal region wide; zygomatic arch bowed laterally.

_Comparisons._--From _Dipodomys ordii richardsoni_, _D. o. montanus_ differs as follows: Size smaller; color darker in all pigmented areas; ventral stripe of tail continuous to end of pencil in all specimens, whereas in _D. o. richardsoni_ the stripe is incomplete in most specimens. In all specimens the dorsal and ventral stripes of the tail are darker in _D. o. montanus_; skull smaller in all measurements taken; jugal straight or nearly so, as contrasted to bowed laterally; pterygoid fossae shallower and more ovoid, that is to say, wings of pterygoid flare laterally; ventral projection of auditory bullae more pronounced; rostrum, immediately in front of zygomatic process of maxilla, nearly parallel to median plane along long axis of skull, while in _D. o. richardsoni_ this union forms a decided obtuse angle; paroccipital processes smaller; foramen magnum smaller and more ovoid as opposed to larger and more circular.

From _Dipodomys ordii evexus_, _D. o. montanus_ differs as follows: Size smaller in all measurements taken except width across auditory bullae which is greater; color darker, ventral stripe of tail continuous to end of pencil; least width of supraoccipital less (2.5 mm. in _D. o. montanus_ and 3.5 mm. in _D. o. evexus_); extension of premaxillae posterior to nasals greater; braincase more inflated dorsally; bullae relatively as well as actually larger and more inflated ventrally; pterygoid fossae narrower anteroposteriorly and wider laterally than in _D. o. evexus_; jugal straight or nearly so as contrasted to bowed laterally; lacrimal processes smaller.

For comparison with _Dipodomys ordii medius_ see account of that subspecies.

_Remarks._--This subspecies of _Dipodomys ordii_ appears to be restricted to the San Luis Valley of Colorado and New Mexico. Intergradation, between _Dipodomys ordii ordii_ and _D. o. montanus_, is noted in animals from Gran Quivira, Mesa Jumanes, New Mexico. These animals have the frontomaxillary suture and extension of the premaxilla as in _D. o. ordii_ and the nasals and inflation of the auditory bullae as in _D. o. montanus_. In the majority of characters they are, however, referable to the latter. Intergradation is noted also in animals from 4 miles southwest of Cimmaron, New Mexico, in that they resemble _D. o. richardsoni_ in the shape of the nasals and the width and length of the rostrum but in the remainder of the characters studied resemble _D. o. montanus_ to which they are referred.

Baird, in the original description, gives "near Fort Massachusetts" as the type locality for this subspecies. Miller (1923) lists the type locality as "Fort Massachusetts (now Fort Garland)." Fort Massachusetts and Fort Garland are two different ex-army posts. Old Fort Massachusetts was situated on what is now the Trinchera Ranch which is north of the town of Fort Garland. Old Fort Garland is approximately one-half mile south of the town of Fort Garland. The two abandoned army posts were no more than twelve miles apart. In 1946, at neither abandoned post could I find any habitat suitable for kangaroo rats.

_Specimens examined._--Total, 148, distributed as follows:

=Colorado=: _Saguache County_: Saguache, 1 (USBS). _Alamosa County_: 1.6 mi. NE Medano Springs Ranch Headquarters, 8 (MVZ); Great Sand Dunes National Monument, 10 (MVZ); 8 mi. S Great Sand Dunes National Monument, 4 (MVZ); Medano Ranch, 15 mi. NE Mosca, 11 (2 USBS; 9 MVZ); 22 mi. E Mosca, 5 (AMNH); Alamosa, 1 (UM). _Conejos County_: Antonito, 1 (USBS); 7 mi. E Antonito, 3 (USBS); 12 mi. E Antonito, 2 (USBS). _Costilla County_: 4-1/2 mi. N Blanca, 8100 ft., 3 (MVZ); 1 mi. NE Blanca, 7950 ft., 1 (MVZ); 3 mi. NW Fort Garland, 6 (CMNH); 1 mi. NW Fort Garland, 3 (MVZ); 15 mi. W Fort Garland, 7800 ft., 4 (KU); Fort Garland, 64 (31 USBS; 28 LACM; 5 MVZ); 5 mi. SSE Fort Garland, 4 (AMNH); 5 mi. S Fort Garland, 2 (AMNH).

=New Mexico=: _Colfax County_: 4 mi. SW Cimmaron, 5 (AMNH); 3 mi. SE Cimmaron, 8 (AMNH); 1-1/2 mi. W Philmont Ranch Headquarters, 2 (AMNH).

=Dipodomys ordii cinderensis= Hardy

_Dipodomys ordii cinderensis_ Hardy, Proc. Biol. Soc. Washington, 57:53, October 31, 1944.

_Type._--Male, no. 4611, Mus. Zool., Univ. Utah; at approximately 4,000 ft. on sandy soil, immediately north of the northern of two large cinder cones in Diamond Valley, 10 mi. N St. George, Washington County, Utah; obtained on February 13, 1944, by Ross Hardy, original no. 2690.

_Range._--Diamond Valley, Washington County, Utah, north through Mountain Meadows, east as far as Cedar City, Iron County, Utah, north through the Escalante Desert to Lund, Iron County, and west almost to the Utah-Nevada boundary; marginal occurrences, all in Utah are: 11 mi. SE Lund; N end Mountain Meadows; Diamond Valley; 10 mi. W Cedar City; 4-1/2 mi. NW Summit and 6 mi. W Parowan.

_Diagnosis._--Size small (see measurements). Color dark, upper parts near Buffy Brown, strongly suffused with black, purest on sides and flanks; pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail, arietiform markings, black. Skull small; rostrum narrow; auditory bullae relatively as well as actually well inflated; external auditory meatus small; interparietal region narrow.

_Comparisons._--From _Dipodomys ordii fetosus_, _D. o. cinderensis_ differs in: Size smaller; color darker; skull smaller in all measurements taken.

From _Dipodomys ordii panguitchensis_, _D. o. cinderensis_ differs as follows: Size smaller; color lighter; skull smaller except for auditory bullae which are larger; external auditory meatus smaller; maxillary tooth-row longer.

Compared with _Dipodomys ordii longipes_ and _Dipodomys ordii cupidineus_, _D. o. cinderensis_ is smaller, darker and can easily be distinguished.

For comparisons with _Dipodomys ordii celeripes_ and _Dipodomys ordii utahensis_ see accounts of those subspecies.

_Remarks._--This race confined to Utah, and inhabiting northern Washington County and most of Iron County, is restricted almost exclusively to areas of loose shifting sand. Intergradation with _Dipodomys ordii fetosus_ occurs near Lund. The animals from this locality intergrade in size of body and in color, but in the majority of cranial characters resemble _D. o. cinderensis_. In all characters studied _D. o. cinderensis_ appears to be more closely related to _Dipodomys ordii utahensis_ than to any other subspecies with which it comes into actual contact.

Animals from near Parowan have both cranial and external characters by which they could be referred to either _D. o. panguitchensis_ or _D. o. cinderensis_. Owing to the existence of the physical barrier (Cedar Mountains) separating the two populations, they are referred to _D. o. cinderensis_. _Dipodomys ordii cinderensis_ is not a well differentiated race but appears to possess characters sufficiently diagnostic to distinguish it from contiguous forms.

_Specimens examined._--Total, 74, all from Utah, distributed as follows: _Iron County_: 11 mi. SE Lund, 50 (46 RH; 4 MVZ); 4-1/2 mi. NW Summit and 6 mi. W Parowan, 9 (RH); 10 mi. W Cedar City, 1 (USAC); 5 mi. W Cedar City, 1 (USAC); Cedar City, 2 (BYU). _Washington County_: Diamond Valley, 9 (RH); N end Mountain Meadows, 2 (RH).

=Dipodomys ordii fetosus= Durrant and Hall

_Dipodomys ordii fetosus_ Durrant and Hall, Mammalia, 3:14, March, 1939.

_Type._--Female, adult, no. 48451, Museum of Vertebrate Zoology, University of California; 2 mi. N Panaca, 4,800 ft., Lincoln County, Nevada; obtained on June 24, 1931, by Ward C. Russell, original no. 1658.

_Range._--Southeastern Nevada and western Beaver and Millard counties, Utah; marginal occurrences in Nevada, 2 mi. SE Pioche, 15 mi. WSW Sunnyside, 16-1/2 mi. WSW Sunnyside, 14 mi. NNE Sharp, 8-1/2 mi. NE Sharp, 15 mi. S Groom Baldy, 10 mi. E Crystal Spring, Panaca; in Utah, Pine Valley, 50 mi. W Milford and 5 mi. S Garrison.

_Diagnosis._--Size medium (see measurements). Color dark, entire dorsal surface (_16''_) between Pinkish Cinnamon and Cinnamon-Buff, purest on sides and flanks with strong admixture of black in upper parts; cheeks white; pinnae of ears, arietiform markings, plantar surfaces of hind feet, dorsal and ventral stripes of tail, blackish. Skull medium in size; rostrum wide and short; interorbital region narrow; braincase but slightly vaulted; lacrimal processes large; zygomatic arches weak and bowed laterally; pterygoid fossae large and subcircular.

_Comparisons._--From _Dipodomys ordii utahensis_, _D. o. fetosus_ differs as follows: Hind foot longer; color lighter; skull larger; rostrum, relatively as well as actually, shorter and wider; nasals longer and wider; interorbital region narrower; braincase less vaulted; interparietal region narrower; auditory bullae more inflated laterally, posteriorly and ventrally; foramen magnum smaller.

From _Dipodomys ordii celeripes_, _D. o. fetosus_ differs as follows: Larger; color darker; arietiform markings present; skull larger; rostrum longer and wider; nasals longer and less inflated distally; interorbital region wider; auditory bullae somewhat more inflated; zygomatic arches more robust.

For comparisons with _Dipodomys ordii monoensis_, _D. o. columbianus_, _D. o. pallidus_, _D. o. panguitchensis_ and _D. o. cinderensis_ see accounts of those subspecies.

_Remarks._--_Dipodomys ordii fetosus_ has a small geographic range. Hall (1946:416) points out that the interorbital breadth in topotypes is less than in those from any other part of the range. This feature, therefore, is not useful in characterizing this subspecies. Intergradation with _Dipodomys ordii columbianus_ is noted in the greater total length and the somewhat darker color in animals from Coal Valley and Garden Valley, Nevada. In the part of the range which lies in Utah, none of the animals is typical and all are intergrades in color and cranial characters with _Dipodomys ordii celeripes_.

_Specimens examined._--Total, 136, distributed as follows:

=Nevada=: _Nye County_: White River Valley, 15 mi. WSW Sunnyside, 5500 ft., 26 (MVZ); White River Valley, 16-1/2 mi. WSW Sunnyside, 5500 ft., 6 (MVZ); 14 mi. NNE Sharp, 1 (MVZ); Garden Valley, 15 mi. NE Sharp, 1 (MVZ); Garden Valley, 14-1/2 mi. NE Sharp, 3 (MVZ); 8-1/2 mi. NE Sharp, 17 (MVZ). _Lincoln County_: E side Coal Valley, 14 mi. N Seeman Pass, 4850 ft., 4 (MVZ); 2 mi. SE Pioche, 1 (MVZ); E side Coal Valley, 10 mi. N Seeman Pass, 1 (MVZ); Desert Valley, 20 mi. SW Pioche, 1 (MVZ); 2 mi. N Panaca, 4800 ft., 17 (16 MVZ; 1 CAS); Desert Valley, 21 mi. W Panaca, 10 (MVZ); Crystal Spring, Pahranagat Valley, 4000 ft., 2 (MVZ); 10 mi. E Crystal Springs, 5000 ft., 1 (MVZ); 15 mi. S Groom Baldy, 1 (MVZ).

=Utah=: _Millard County_: 5 mi. S Garrison, 5400 ft., 12 (MVZ); Pine Valley, Sec. 33, T. 25 S, R. 17 W, 5000 ft., 16 (UU); Warm Cove, Sec. 34, T. 25 S, R. 18 W, 5500 ft., 2 (UU); Desert Range Experiment Station, 50 mi. W Milford, 5252 ft., 10 (9 UU; 1 BYU).

=Dipodomys ordii utahensis= (Merriam)

_Perodipus montanus utahensis_ Merriam, Proc. Biol. Soc. Washington, 17:143, July 14, 1904.

_Perodipus ordii utahensis_, Goldman, Proc. Biol. Soc. Washington, 30:113, May 23, 1917.

_Dipodomys ordii columbianus_, Grinnell, Journ. Mamm., 2:96, May 2, 1921.

_Dipodomys ordii columbianus_, Hall, Univ. California Publ. Zool., 37:5, April 10, 1931 (part--the part from Ogden, Utah.)

_Type._--Male, adult, no. 55115, U. S. Nat. Mus. Biol. Surv. Coll.; Ogden, Weber County, Utah; obtained on July 15, 1893, by Vernon Bailey, original no. 4085.

_Range._--Between Great Salt Lake and the Wasatch Mountains from extreme northern Utah, south to northern Sevier County, Utah; marginal occurrences, all in Utah, are: Promontory Point, Ogden, St. John, Cedar Valley, Nephi, Aurora, Spring City, Provo and 4 mi. N Draper.

_Diagnosis._--Size small (see measurements). Color dark, entire dorsal surface (_a_) between Cinnamon-Buff and Clay Color, purest on sides, flanks and cheeks, with heavy admixture of black in upper parts; arietiform markings, pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail blackish. Skull small; rostrum short and narrow; interorbital region moderately wide; interparietal large, spatulate anteriorly; lacrimal processes relatively large; braincase vaulted; zygomatic arches robust and straight; auditory bullae relatively, as well as actually, greatly inflated.

_Comparisons._--From _Dipodomys ordii marshalli_, _D. o. utahensis_ differs as follows: Size smaller; color darker; skull smaller; rostrum longer and narrower; interorbital region wider; lacrimal processes larger; interparietal region larger; auditory bullae less inflated; palate longer and narrower.

From _Dipodomys ordii pallidus_, _D. o. utahensis_ differs in: Size smaller; color darker; skull smaller; rostrum shorter and narrower; interorbital region narrower; auditory bullae less inflated laterally, posteriorly and ventrally; interparietal region larger; lacrimal processes smaller; foramen magnum with ventral notch as opposed to rounded ventrally; pterygoid fossae circular as opposed to subcircular; palate longer and narrower.

From _Dipodomys ordii cinderensis_, _D. o. utahensis_ differs as follows: Size larger, except hind foot which is shorter; color somewhat lighter, more reddish; skull larger; rostrum longer; nasals longer; braincase more vaulted; pterygoid fossae circular as opposed to subcircular; auditory bullae less inflated laterally but more inflated ventrally.

For comparisons with _Dipodomys ordii columbianus_, _D. o. fetosus_, _D. o. marshalli_, _D. o. panguitchensis_ and _D. o. cineraceus_ see accounts of those subspecies.

_Remarks._--The systematic status of _D. o. utahensis_ has long been in doubt. Several workers have, at various times, considered it to be indistinguishable from _Dipodomys ordii columbianus_. Durrant and Setzer (1945:29) recognized it as a valid subspecies and gave diagnostic characters by which it could be distinguished from _D. o. columbianus_.

Intergradation has been noted in specimens from the eastern and southeastern shores of Great Salt Lake. In color and the width of the auditory bullae these specimens are intermediate between _D. o. utahensis_ and _Dipodomys ordii marshalli_ but in the sum total of characters are referable to the latter. Specimens from 20 miles southwest of Nephi and from U. B. (Yuba) Dam are darker and intermediate in rostral width and breadth of the auditory bullae but are referable to _Dipodomys ordii celeripes_.

_Specimens examined._--Total, 91, all from Utah, distributed as follows: _Box Elder County_: Promontory Point, 1 (USNM). _Weber County_: Ogden, 4293 ft., 20 (7 BYU; 7 MVZ; 4 USNM); Little Mountain, 1 (USNM). _Davis County_: Antelope Island, Great Salt Lake, 4250 ft., 5 (USNM). _Tooele County_: Bauer, 4500 ft., 6 (UU); St. John, 4300 ft., 4 (UU); Little Valley, Sheeprock Mountains, 5500 ft., 1 (UU); Clover Creek, Onaqui Mountains, 5500 ft., 1 (UU). _Salt Lake County_: Plain, 4 mi. N Draper, 4500 ft., 1 (UU). _Utah County_: Fairfield, Cedar Valley, 4800 ft., 15 (9 BYU; 6 UU); W Lake Mountains, 9 (BYU); Provo, 4510 ft., 10 (MVZ); Sand Dunes W Curtis Station, 4 (BYU). _Juab County_: Nephi, 2 (1 USNM; 1 MVZ); 4 mi. W Nephi, 1 (RH). _San Pete County_: Spring City, 4 (LACM). _Sevier County_: 1 mi. W Aurora, 5190 ft., 6 (5 UU; 1 USNM).

=Dipodomys ordii columbianus= (Merriam)

_Perodipus ordi columbianus_ Merriam, Proc. Biol. Soc. Washington, 9:115, June 21, 1894.

_Dipodomys phillipii_, Baird, U. S. P. R. R. Expl. and Surveys, Gen. Rept., p. 412, 1857 (part--the part from Ft. Walla Walla, O. T.).

_Cricetodipus ordii columbianus_, Trouessart, Catalogus Mammalium, 1:581, 1897.

_Perodipus ordii columbianus_, Goldman, Proc. Biol. Soc. Washington, 30:113, May 23, 1917.

_Dipodomys ordii columbianus_, Grinnell, Journ. Mamm., 2:96, May 2, 1921.

_Type._--Female, adult, no. 24181/31594, U. S. Nat. Mus., Dept. of Agriculture, Coll.; Umatilla, Plains of Columbia, Umatilla County, Oregon; obtained on October 18, 1890, by Clark P. Streator, original no. 386.

_Range._--Southeastern Washington, eastern Oregon, southwestern Idaho, northwestern, northern and most of northeastern Nevada; marginal occurrences are: in Washington, 2 mi. SW Paterson, 4 mi. E Burbank and Wallula; in Oregon, 7 mi. E Madras, 2 mi. E Prineville and Guano Valley; in California, Eagleville, Red Rock, Observation Peak, 5 mi. E Litchfield, Honey Lake, Vinton; in Nevada, 3-1/2 mi. E Flanigan, 6 mi. S Pahrum Peak, 2-1/2 mi. E and 11 mi. N Gerlach, 2 mi. SW Quinn River Crossing, 1 mi. SE Tuscarora, 5 mi. N Beowawe, 1/2 mi. S Beowawe, 2-1/2 mi. NE Smiths Creek Ranch, Bells Ranch, 5 mi. W Austin, 8 mi. W Eureka, 4 mi. S Shoshone, 5 mi. SE Greens Ranch, and 22 mi. N Deeth; in Idaho, 8 mi. W Rodgerson, 6 mi. SW American Falls, 4 mi. NE American Falls, 5 mi. NW Michaud, Arco, Hammett and Payette; in Oregon, Umatilla.

_Diagnosis._--Size medium (see measurements). Color dark, entire dorsal surface (_16''_) between Pinkish Cinnamon and Cinnamon-Buff, purest on sides and flanks with strong admixture of black on upper parts; cheeks white; arietiform markings, pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail, blackish. Skull medium in size; rostrum relatively long and narrow; nasals long and expanded distally; interorbital region narrow; lacrimal processes small; braincase but slightly vaulted; auditory bullae relatively greatly inflated; pterygoid fossae circular; zygomatic arches robust.

_Comparisons._--From _Dipodomys ordii utahensis_, _D. o. columbianus_ differs as follows: Color lighter, dorsal and ventral stripes of tail brownish as opposed to black; ventral stripe of tail, in most specimens, incomplete to end of pencil as opposed to complete; lacrimal processes smaller; extension of premaxillae dorsad wider; interparietal generally narrower, smaller, quadrangular and truncate anteriorly, as opposed to spatulate and rounded anteriorly; braincase less vaulted; zygomatic arches bowed laterally as opposed to straight; styloid processes larger; cutting edge of upper incisors narrower.

From _Dipodomys ordii fetosus_, _D. o. columbianus_ differs in: Hind foot shorter; color generally darker; skull larger; rostrum shorter and wider; nasals somewhat shorter; braincase more vaulted; auditory bullae less inflated; interparietal region wider; ventral border of foramen magnum more rounded (less indented); zygomatic arches straight as opposed to bowed laterally.

For comparisons with _Dipodomys ordii inaquosus_, _Dipodomys ordii monoensis_ and _Dipodomys ordii celeripes_ see accounts of those subspecies.

_Remarks._--In most subspecies of _Dipodomys ordii_ having large geographic ranges, there is a certain amount of variation, but _D. o. columbianus_ remains relatively stable throughout its large range. Where extreme variation is noted in _D. o. columbianus_ it is obviously the result of intergradation. This intergradation is noted between _Dipodomys ordii monoensis_ and _D. o. columbianus_ in Lyon County, Nevada, where the animals are referable to the former race cranially but to the latter on the basis of color. Animals from Kelton, Utah, are in color as _Dipodomys ordii marshalli_ and cranially combine characters of _D. o. columbianus_, _D. o. utahensis_ and _D. o. marshalli_. The sum total of their characters places them with _D. o. marshalli_. Durrant and Setzer (1945:29), and the present writer in this account, do not record any animals from Utah as belonging to _D. o. columbianus_. Nevertheless, the influence of _D. o. columbianus_ is seen in the animals from Kelton, Utah.

_Specimens examined._--Total, 588, distributed as follows:

=Washington=: _Benton County_: Blalock Island, 2 mi. SW Paterson, 2 (MVZ). _Walla Walla County_: 4 mi. E Burbank, 4 (MVZ); 2 mi. SSE Burbank, 27 (MVZ); Wallula, 7 (4 MVZ; 3 DRD).

=Oregon=: _Gilliam County_: Arlington, 1 (MVZ). Morrow County: 2-1/2 mi. SW Irigon, 6 (MVZ); Cecil, 1 (MVZ). _Umatilla County_: Umatilla, 10 (MVZ). _Jefferson County_: 7 mi. E Madras, 2 (DRD). _Crook County_: 2 mi. NE Prineville, 1 (MVZ); 7 mi. W Prineville, 8 (MVZ); 4 mi. SW Prineville, 23 (MVZ); Crooked River, at mouth of Bear Creek, 8 (MVZ). _Lake County_: Fort Rock, 1 (DRD); NE edge Alkali Lake, 8 (MVZ); 9 mi. S Adel, mouth 20 Mile Creek, 1 (MVZ); Guano Ranch, Guano Valley, 2 (DRD). _Harney County_: Malheur Lake, 9 (LACM); Narrows, 1 (DRD); 1 mi. S Narrows, 3 (MVZ); 5 mi. SW Narrows, 19 (MVZ); Smith Creek, 10 mi. SE Diamond, 1 (MVZ); Lake Alvord, 1 (MVZ); 1-1/2 mi. E Denio, 4 (MVZ). _Malheur County_: 3 mi. N Vale, 2 (MVZ); 8 mi. N Jordan Valley, 1 (MVZ); 1/2 mi. S Rome, 5 (MVZ); 1 mi. S Rome, 11 (MVZ).

=Idaho=: _Payette County_: Payette, 1 (DRD). _Butte County_: Arco, 1 (MVZ). _Elmore County_: Hammett, 1 (MVZ). _Bingham County_: 5 mi. E Shelley, 1 (MVZ); Blackfoot, 5 (MVZ); 3 mi. S Blackfoot, 6 (MVZ); Aberdeen, 1 (MVZ). _Owyhee County_: S bank Snake River, Homedale, 13 (MVZ); Indian Cove, 4 (MVZ); 5 mi. SE Murphy, 3 (MVZ); Castle Creek, 8 mi. S Oreana, 1 (MVZ); S Fork Owyhee River, 12 mi. N Nevada line, 1 (MVZ). _Minidoka County_: Acequia, 8 (MVZ); 4 mi. N Rupert, 2 (MVZ). _Twin Falls County_: Salmon Creek, 8 mi. W Rodgerson, 7 (MVZ). _Power County_: 5 mi. NW Michaud, 4 (MVZ); 4 mi. NE American Falls, 4 (MVZ); 6 mi. SW American Falls, 10 (MVZ).

=California=: _Modoc County_: Eagleville, 12 (CAS); 2 mi. E Eagleville, 7 (CAS); 2-1/2 mi. E Eagleville, 24 (CAS); 3 mi. E Eagleville, 6 (CAS); 5 mi. E Eagleville, 3 (CAS). _Lassen County_: 2 mi. W Red Rock P. O., 1 (MVZ); 1 mi. W Red Rock P. O., 4 (MVZ); Dransfield, 6 mi. E Ravendale, 5300 ft., 4 (CAS); 7 mi. E Ravendale, 1 (MVZ); 7 mi. N Observation Peak, 21 (MVZ); 6 mi. N Observation Peak, 7 (MVZ); Observation Peak, 31 (MVZ); Pete's Valley, 4 (MVZ); 5 mi. E Litchfield, 12 (MVZ); 6 mi. W Wendell, 3975 ft., 3 (CAS); 8 mi. SW Wendell, 5 (CAS); Honey Lake, 2 (LACM); 4-1/2 mi. WNW Stacy, 5 (MVZ); 3 mi. NW Warm Springs, 1 (MVZ). _Plumas County_: Beckwith, 1 (DRD); 2 mi. WNW Vinton, 2 (MVZ); Vinton, 18 (14 LACM; 4 MVZ); 1 mi. E Vinton, 7 (MVZ); near Vinton, 21 (DRD).

=Nevada=: _Washoe County_: 3 mi. N Vya, 3 (MVZ); 4-1/2 mi. NE Painted Point, 4 (MVZ); 8-1/2 mi. E Vya, 1 (MVZ); 3 mi. E Painted Point, 1 (MVZ); Long Valley Ranch, 3 mi. S Vya, 1 (MVZ); 10-1/2 mi. S Vya, 1 (MVZ); 11 mi. S Vya, 2 (MVZ); 13 mi. S Vya, 4 (MVZ); Hausen, 4800 ft., 8 (MVZ); 10 mi. SE Hausen, 4675 ft., 7 (MVZ); 2-1/2 mi. E and 11 mi. N Gerlach, 4050 ft., 4 (MVZ); Smoke Creek, 9 mi. E California line, 3900 ft., 5 (MVZ); 40° 28' N Lat., 6 mi. E California line, 4000 ft., 3 (MVZ); Horse Canyon, 3 mi. NW Pahrum Peak, 5000 ft., 1 (MVZ); Fox Canyon, 6 mi. S Pahrum Peak, 4800 ft., 4 (MVZ); N side Sand Pass, 3950 ft., 2 (MVZ); 4 mi. NW Flanigan, 4200 ft., 1 (MVZ); 3-1/2 mi. NW Flanigan, 4200 ft., 1 (MVZ); 3-1/2 mi. E Flanigan, 2 (MVZ); 2-3/4 mi. SW Pyramid, 4300 ft., 2 (MVZ). _Humboldt County_: 1 mi. S Denio, Oregon, 4200 ft., 6 (MVZ); Quinn River Crossing, 4100 ft., 1 (MVZ). _Elko County_: Mary's River, 22 mi. N Deeth, 3 (MVZ); 1 mi. SE Tuscarora, 5900 ft., 2 (MVZ); 5 mi. W Halleck, 5200 ft., 7 (MVZ); 3 mi. W Halleck, 5300 ft., 2 (MVZ). _Lander County_: 1 mi. E Battle Mountain, 1 (MVZ); Reese River Valley, 6 mi. N Austin, 2 (MVZ); Malloy Ranch, 5 mi. W Austin, 3 (MVZ); 2-1/2 mi. NE Smiths Creek Ranch, 5800 ft., 1 (MVZ); Campbell Creek, 6900 ft., 3 (MVZ); Campbell Creek Ranch, 5500 ft., 8 (MVZ). _Eureka County_: 5 mi. N Beowawe, 7 (MVZ); 1/2 mi. S Beowawe, 1 (MVZ); Pine Creek, 2 mi. E Palisades, 7 (MVZ); Evans, 4 (MVZ); Winzell, 3 (MVZ); 4 mi. SE Romano, Diamond Valley, 1 (MVZ); 8 mi. W Eureka, 12 (MVZ). _White Pine County_: 5 mi. SE Greens Ranch, Steptoe Valley, 1 (MVZ); Cherry Creek, 6600 ft., 2 (MVZ); 1 mi. E Illipah, 6100 ft., 3 (MVZ); 5-1/2 mi. SE Ely, 6500 ft., 5 (MVZ); Spring Valley, 5900 ft., 4 mi. S Shoshone, 6 (MVZ). _Nye County_: Bells Ranch, Reese River, 6890 ft., 1 (MVZ).

=Dipodomys ordii idoneus= new subspecies

_Type._--Male, adult, no. 90029, Museum of Zoology, University of Michigan; San Juan, 12 mi. W Lerdo, 3,800 ft., Durango, Mexico; obtained on March 1, 1946, by F. and F. Hammerstrom.

_Range._--Known only from the type locality.

_Diagnosis._--Size small (see measurements). Color pale, entire dorsal surface (c) between Light Ochraceous-Buff and Ochraceous-Buff, purest on sides, flanks and cheeks; upper parts but slightly washed with black; arietiform markings, lateral parts of pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail, brownish; medial part of pinnae of ears flesh-colored. Skull medium in size; rostrum wide and relatively long; braincase but slightly inflated; least interorbital width great; interparietal region relatively narrow; upper incisors strongly recurved; zygomatic arches relatively heavy and slightly bowed laterally; auditory bullae greatly inflated ventrally, laterally and posteriorly.

_Comparisons._--From _Dipodomys ordii ordii_, _D. o. idoneus_ differs in: Size smaller; color lighter; skull larger; nasals longer and somewhat more inflated distally as opposed to straight; interorbital width greater; breadth across maxillary arches greater; interparietal region narrower; auditory bullae more inflated posteriorly, laterally and ventrally and projecting anteriorly into orbit; extension of nasals anterior to upper incisors less; zygomatic arches heavier and more bowed laterally; paroccipital processes smaller; foramen magnum elongate as opposed to nearly circular.

From _Dipodomys ordii obscurus_, _D. o. idoneus_ differs as follows: Size smaller; color lighter; skull larger, rostrum wider; nasals shorter and more expanded distally; interorbital region wider; width across maxillary arches greater; interparietal region narrower; auditory bullae more inflated laterally, posteriorly and ventrally; zygomatic arches shorter, heavier and less bowed laterally.

From _Dipodomys ordii palmeri_, _D.o. idoneus_ differs in: Size smaller; color lighter; skull larger; rostrum shorter and wider; nasals shorter and more expanded distally; interorbital region wider; auditory bullae more inflated laterally, posteriorly and ventrally; zygomatic arches heavier.

From _Dipodomys ordii fuscus_, _D. o. idoneus_ differs as follows: Size smaller; color lighter; skull smaller; rostrum narrower and shorter; interorbital width greater; braincase more vaulted; nasals longer; interparietal region generally wider; auditory bullae less inflated; breadth across maxillary arches greater; zygomatic arches heavier and more bowed laterally; pterygoid fossae ovoid as opposed to subcircular; occipital condyles more anterior to dorsal evagination when viewed ventrally.

_Dipodomys ordii idoneus_ differs from _Dipodomys ordii attenuatus_ in larger size, generally darker color and larger skull.

_Remarks._--This subspecies of _Dipodomys ordii_ is paler than either of the subspecies with adjoining geographic ranges. Measurements of the skull, in proportion to external measurements, are larger than in any other subspecies of _Dipodomys ordii_. Cranially, this new subspecies is more closely allied to _Dipodomys ordii fuscus_ but in color appears to be much closer to _Dipodomys ordii attenuatus_ from which it differs markedly in cranial features.

_Specimens examined._--Total, 3, all from Durango, distributed as follows: San Juan, 12 mi. W Lerdo, 3 (UM).

=Dipodomys ordii priscus= Hoffmeister

_Dipodomys ordii priscus_ Hoffmeister, Proc. Biol. Soc. Washington, 55:167, December 31, 1942.

_Perodipus longipes_, Allen, Bull. Amer. Mus. Nat, Hist., 8:246, November, 1896 (part--the part from Kinney Ranch, Wyoming).

_Perodipus montanus richardsoni_, Cary, N. Amer. Fauna, 33:141, August 17, 1911 (part--the part from Lay, Colorado).

_Periodipus_ [_Dipodomys_] _ordii luteolus_, Svihla, Journ. Mamm.; 12:262, August, 1931 (part--the part from Linwood, Utah).

_Type._--Male, no. 89119, Mus. Vert. Zool., Univ. California; Kinney Ranch, 21 mi. S Bitter Creek, 7100 ft., Sweetwater County, Wyoming; obtained on September 16, 1939, by Donald T. Tappe, original no. 766.

_Range._--Southwestern Wyoming, extreme northeastern Utah and northwestern Colorado; marginal occurrences are: in Wyoming, 7 mi. N Ft. Washakie and 10 mi. SW Granger; in Colorado, Lay and Snake River south of Sunny Peak.

_Diagnosis._--Size medium (see measurements). Color light, entire dorsal surface between (c) Light Ochraceous-Buff and Ochraceous-Buff, purest on sides, flanks and cheeks; upper parts slightly suffused with black; arietiform markings, pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail, grayish to blackish in different individuals. Skull medium in size; rostrum long and narrow; nasals long; auditory bullae relatively narrow and skull long, giving appearance of much narrower skull than is actually the case; zygomata weak; upper incisors moderately wide at cutting edge.

_Comparisons._--From _Dipodomys ordii uintensis_, _D. o. priscus_ differs as follows: Hind foot longer; color lighter in all pigmented areas, and skull smaller in all measurements taken.

From _Dipodomys ordii sanrafaeli_, _D. o. priscus_ differs in: Color decidedly less red in upper parts; ventral stripe of tail not continuous to end of pencil; nasals longer; auditory bullae less inflated.

For comparisons with _Dipodomys ordii luteolus_ and _Dipodomys ordii terrosus_ see accounts of those subspecies.

_Remarks._--The characters of this subspecies are stable throughout most of its geographic range. It is not known to intergrade with adjacent forms. One specimen, a male, available from the Snake River, south of Sunny Peak, Colorado, however, is not typical of _D. o. priscus_, in that it has a wider and deeper rostrum than any other specimen from the entire range. Between _D. o. priscus_ and _D. o. luteolus_, the skull, but not the color, provides diagnostic differences.

The Red Desert of Wyoming is mostly sandy but there are large exposures of rock and gravel. At the type locality of _D. o. priscus_ rockier soil predominates but is interspersed with stabilized sand dunes where the kangaroo rats are abundant. Traps set on the rocky soils, in a continuous line between the dunes, yielded no kangaroo rats.

Kangaroo rats in the area of the Kinney Ranch, Wyoming, apparently form a good source of food for owls, since many bones (jaws and limb elements) were found in owl pellets at the bases of cliffs approximately 5 miles northeast of the ranch buildings.

_Specimens examined._--Total, 72, distributed as follows:

=Wyoming=: _Fremont County_: 7 mi. N Fort Washakie, 1 (USBS); Fort Washakie, 1 (USBS); Wind River, 1 (USBS). _Sweetwater County_: Eden, 1 (USBS); 5 mi. E Rock Springs, 1 (UM); 10 mi. SW Granger, 13 (UM); Bitter Creek, 9 (6 AMNH; 3 CNHM); Kinney Ranch, 21 mi. S Bitter Creek, 18 (MVZ); Shell Creek, 25 mi. S Bitter Creek, 3 (CM); 30 mi. S Bitter Creek, 3 (KU); 33 mi. S Bitter Creek, 8 (KU). _Carbon County_: 20 mi. W Baggs, 2 (USBS).

=Utah=: _Daggett County_: E bank Green River, 4 mi. E Linwood, 4 (CM).

=Colorado=: _Moffat County_: Snake River, south of Sunny Peak, 1 (USBS); 20 mi. NW Sunbeam, 4 (CM); Bear River, Lay, 1 (USBS). _Rio Blanco County_: W side White River, 1 mi. N Rangely, 1 (CM).

=Dipodomys ordii celeripes= Durrant and Hall

_Dipodomys ordii celeripes_ Durrant and Hall, Mammalia, 3:10, March, 1939.

_Dipodomys ordii columbianus_, Hall, Univ. California Publ. Zool., 37:5, April 10, 1931.

_Type._--Male, adult, no. 1956, Museum of Zoology, University of Utah; Trout Creek, 4600 ft., Juab County, Utah; obtained on May 5, 1937, by Stephen D. Durrant, original no. 1168.

_Range._--Eastern Nevada, western and west-central Utah, east to eastern Sevier County, Utah; marginal occurrences are: in Nevada, Tecoma, Cobre and 8 mi. SE Mt. Moriah; in Utah, E side Clear Lake, U. B. (Yuba) Dam, 10 mi. SW Nephi, and Trout Creek.

_Diagnosis._--Size small (see measurements). Color pale, entire dorsal surface Pinkish Buff, purest on sides, flanks and cheeks, with but slight suffusion of black in upper parts; pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail, brownish. Skull small; rostrum relatively short and wide; nasals relatively short; lacrimal processes small; braincase but slightly vaulted; auditory bullae but little inflated; interorbital region narrow; styloid processes project on ventral surface of auditory bullae beyond middle of external auditory meatus; zygomatic arches robust and bowed laterally; pterygoid fossae ovoid.

_Comparisons._--From _Dipodomys ordii marshalli_, _D. o. celeripes_ differs as follows: Size smaller, hind foot longer, tail shorter; color lighter; skull smaller; rostrum wider and shorter; interorbital region narrower; auditory bullae less inflated; lacrimal processes smaller; palate shorter; pterygoid fossae larger.

From _Dipodomys ordii cinderensis_, _D. o. celeripes_ differs as follows: Size smaller, tail shorter; color lighter; rostrum wider and shorter; nasals shorter; interorbital width less; auditory bullae less inflated; foramen magnum wider and shorter; pterygoid fossae more circular.

From _Dipodomys ordii columbianus_, _D. o. celeripes_ differs in: Size smaller; color lighter; rostrum wider and shorter; interorbital width less; interparietal region wider; auditory bullae, generally, less inflated; upper incisors longer and more robust; pterygoid fossae larger.

For comparisons with _Dipodomys ordii fetosus_, _Dipodomys ordii pallidus_ and _Dipodomys ordii panguitchensis_ see accounts of those subspecies.

_Remarks._--It appears that wherever the range of _D. o. celeripes_ meets that of an adjoining race, intergradation occurs freely. Practically all of the Nevadan specimens referable to this subspecies are intergrades with _Dipodomys ordii columbianus_ in size and color. Specimens from west of Delta, Utah, are intermediate in size between _Dipodomys ordii pallidus_ and _D. o. celeripes_ but their cranial characters are more as in _D. o. celeripes_. Intergrades with _Dipodomys ordii utahensis_ are discussed under the account of that subspecies.

The characters differentiating _D. o. celeripes_ from any contiguous subspecies are not present in every specimen even in the type series.

_Specimens examined._-Total, 96, distributed as follows:

=Nevada=: _Elko County_: 13 mi. N Montello, 5000 ft., 2 (MVZ); 1-1/2 mi. N Tecoma, 4900 ft., 6 (MVZ); Tecoma, 4900 ft., 8 (MVZ); Cobre, 6100 ft., 3 (MVZ); Salt Springs, 4200 ft., 1 (MVZ). _White Pine County_: 2 mi. W Smith Creek Cave, 6300 ft., Mt. Moriah, 2 (MVZ); Hendry Creek, 8 mi. SE Mt. Moriah, 6200 ft., 1 (MVZ).

=Utah=: _Tooele County_: Clifton Flat, 7 mi. SW Gold Hill, 6149 ft., 4 (UU); Parrish Ranch, 5 mi. N Ibapah, 5175 ft., 1 (UU); Ibapah, 5000 ft., 23 (UU). _Juab County_: Trout Creek, 4600 ft., 21 (19 UU; 1 USAC; 1 MVZ); 20 mi. SW Nephi, 2 (UU); U. B. (Yuba) Dam, Sevier River, 5000 ft., 10 (UU). _Millard County_: 4 mi. S Gandy, 5000 ft., 1 (MVZ); Smith Creek, 6 mi. S Gandy, 5400 ft., 2 (MVZ); Hendry Creek, 5000 ft., 17 mi. S Gandy, 4 (MVZ); Oak City, 5000 ft., 1 (UU); White Valley, 60 mi. W Delta, 1 (UU); 35 mi. W Delta, 1 (UU); East side Clear Lake, 4600 ft., 4 (3 UU; 1 USAC); 2 mi. E Clear Lake, 4600 ft., 2 (UU).

=Dipodomys ordii cineraceus= Goldman

_Dipodomys ordii cineraceus_ Goldman, Journ. Mamm., 20:352, August 14, 1939.

_Type._--Male, no. 263890, U. S. Nat. Mus. Biol. Surv. Coll.; Dolphin Island, Great Salt Lake, 4250 ft., Box Elder County, Utah; obtained on June 4, 1938, by William H. Marshall, original no. 57.

_Range._--Dolphin Island, Great Salt Lake, Utah.

_Diagnosis._--Size medium (see measurements). Color pale, upper parts near Pale Pinkish Buff, but lightly washed with black, purest on sides and flanks; arietiform markings, pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail, brownish. Skull medium in size; rostrum short; nasals relatively short; interparietal region relatively wide; auditory bullae but slightly inflated.

_Comparisons._--From _Dipodomys ordii utahensis_, _D. o. cineraceus_ differs in: Size smaller; color lighter; nasals longer; auditory bullae larger; total length of skull greater.

From _Dipodomys ordii marshalli_, _D. o. cineraceus_ differs in: Size smaller; color darker; skull larger in all measurements taken.

_Remarks._--The race _D. o. cineraceus_ along with _Dipodomys microps russeolus_ is found on Dolphin Island, Great Salt Lake, Utah. Dolphin Island is connected with the mainland by a bar that could allow animals from the island to disperse onto the mainland. There are no animals from the mainland, however, that are referable to _D. o. cineraceus_ or to _D. m. russeolus_. The animals available from the mainland, at Kelton, although geographically near Dolphin Island, are referable to _D. o. marshalli_ and to _D. m. bonnevillei_. The paucity of material from the mainland, adjacent to Dolphin Island, may be significant. Future trapping in this area is needed before we can be certain that _D. o. cineraceus_ is isolated.

_Specimens examined._--Total, 2, both from Utah, as follows: _Box Elder County_: Dolphin Island, Great Salt Lake, 4250 ft., 2 (USNM).

=Dipodomys ordii marshalli= Goldman

_Dipodomys ordii marshalli_ Goldman, Proc. Biol. Soc. Washington, 50:223, December 28, 1937.

_Type._--Female, adult, no. 262655, U. S. Nat. Mus. Biol. Surv. Coll.; Bird Island, Great Salt Lake, 4,300 ft., Tooele County, Utah; obtained on June 22, 1937, by W. H. Marshall, X-catalog no. 27969.

_Range._--Bird, Carrington, Badger and Stansbury islands, Great Salt Lake; around western edge of Great Salt Lake north to Kelton, Box Elder County, Utah; around southern and southeastern edge of the lake to mouth of the Jordan River; marginal occurrences are: all in Utah, Kelton, 2 mi. W Grantsville, 14 mi. W Salt Lake City and Bird Island, Great Salt Lake.

_Diagnosis._--Size medium (see measurements). Color pale, entire dorsal surface near Pinkish Buff, purest on sides, flanks and cheeks with but slight suffusion of black on upper parts; arietiform markings, pinnae of ears, plantar surfaces of hind feet, and dorsal and ventral stripes of tail, brownish. Skull medium in size; rostrum narrow and long; pterygoid fossae ovoid; cutting edge of upper incisors narrow; external auditory meatus round and small; jugal straight or nearly so.

_Comparisons._--From _Dipodomys ordii pallidus_, _D. o. marshalli_ differs in: Hind foot smaller; color darker, arietiform markings more distinct; dorsal and ventral stripes of tail more pronounced; skull smaller; palate shorter and wider; jugals lighter; external auditory meatus smaller; cutting edge of upper incisors narrower; nasals shorter and less flared distally.

From _Dipodomys ordii utahensis_, _D. o. marshalli_ differs in: Size smaller; color lighter; skull smaller, except least interorbital width and depth of auditory bullae which are greater; cutting edge of upper incisors narrower; nasals less flared distally.

For comparison with _Dipodomys ordii celeripes_ see account of that subspecies.

_Remarks._--This subspecies was described from Bird Island, Great Salt Lake, and was thought by Marshall (1940:153), who collected the specimens, to be restricted to that island. However, specimens taken over a period of years on the nearby mainland, by students from the University of Utah, are referable to this subspecies. Although these animals from the mainland are referable to _D. o. marshalli_, they have some characteristics of _D. o. utahensis_ from the eastern and southern mainland. Four specimens from Kelton, also on the mainland, are not typical of _D. o. marshalli_; nevertheless, more than half of their characters of taxonomic worth are as in _D. o. marshalli_ to which the animals are referred.

Great Salt Lake has not been so effective in isolating the animals living on the islands as heretofore has been thought. After these supposedly isolated kinds of animals from Great Salt Lake were named, some other workers have shown several of the kinds to have extensive ranges on the mainland. Some of the kinds ranging also on the mainland are: _Dipodomys ordii marshalli_, _Dipodomys microps subtenuis_ and _Peromyscus crinitus pergracilis_. Of the animals named from the islands, I suppose that those which require the semiarid habitat found in this area will all be found to have large ranges on the adjacent mainland and that each of the kinds of animals which do not require the above habitat, and which lived in this region during the Pleistocene, will be found to be restricted to the island from which it was named.

_Specimens examined._--Total, 47, all from Utah, distributed as follows: _Box Elder County_: Kelton, 4300 ft., 7 (5 MVZ; 2 UU). _Tooele County_: 2 mi. W Grantsville, 1 (CAS); Bird Island, Great Salt Lake, 4300 ft., 1 (USNM); Carrington Island, Great Salt Lake, 4300 ft., 1 (USNM); Stansbury Island, Great Salt Lake, 4300 ft., 10 (6 UU; 4 USNM). _Salt Lake County_: 18 mi. W Salt Lake City, 4260 ft., 16 (UU); 17 mi. W Salt Lake City, 4320 ft., 7 (UU); 16 mi. W Salt Lake City, 4300 ft., 3 (UU); 14 mi. W Salt Lake City, 4300 ft., 1 (UU).

=Dipodomys ordii inaquosus= Hall

_Dipodomys ordii inaquosus_ Hall, Proc. Biol. Soc. Washington, 54:58, May 20, 1941.

_Type._--Male, adult, no. 73580, Museum of Vertebrate Zoology, University of California; 11 mi. E and 1 mi. N Jungo, 4,200 ft., Humboldt County, Nevada; obtained on July 26, 1936, by Ward C. Russell, original no. 5026.

_Range._--Southeastern Humboldt and northern Lander counties, Nevada; marginal occurrences, all in Nevada, are: 7 mi. N Winnemucca, 8 mi. E and 1 mi. N Jungo, 15 mi. SW Winnemucca, 23 mi. NW Battle Mountain, Izenhood, and 18 mi. NE Iron Point.

_Diagnosis._--Size medium (see measurements). Color pale, entire dorsal surface Pinkish Buff, purest on sides and flanks with but slight suffusion of black on the upper parts; cheeks white; arietiform marks indistinct, pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail, brownish. Skull medium in size; rostrum short and wide; nasals relatively long and expanded distally; braincase but slightly vaulted; interorbital width narrow; extension of premaxillae posterior to nasals relatively great; interparietal relatively large; pterygoid fossae subcircular; foramen magnum ovoid; auditory bullae relatively greatly expanded ventrally.

_Comparisons._--From _Dipodomys ordii columbianus_, _D. o. inaquosus_ differs as follows: Size larger; color lighter; skull larger; nasals longer; rostrum longer and wider; interorbital region narrower; braincase more vaulted; interparietal larger; auditory bullae more inflated ventrally; pterygoid fossae subcircular as opposed to nearly circular; zygomatic arches more robust.

From _Dipodomys ordii monoensis_, _D. o. inaquosus_ differs in: Size larger; color lighter; skull larger; nasals longer; rostrum wider; interorbital width greater; braincase more vaulted; auditory bullae more inflated laterally, ventrally and posteriorly; interparietal region narrower; pterygoid fossae subcircular as opposed to circular; lacrimal processes larger; foramen magnum ovoid as opposed to circular.

_Remarks._--In pallor _D. o. inaquosus_ closely approaches _Dipodomys ordii celeripes_ from eastern Nevada and western Utah. The two populations are separated, however, by a large area inhabited by the darker _Dipodomys ordii columbianus_. Specimens from 18 mi. NE Iron Point, Nevada, which Hall (1946:413) refers to _D. o. columbianus_, are intergrades in color, size and cranial characters and here are referred to _D. o. inaquosus_ instead of to _D. o. columbianus_. Animals from Toulon are intergrades between _D. o. inaquosus_ and _Dipodomys ordii monoensis_ but are referable to the latter.

_Specimens examined._--Total, 47, all from Nevada, distributed as follows: _Humboldt County_: 18 mi. NE Iron Point, 4600 ft., 1 (MVZ); 7 mi. N Winnemucca, 4400 ft., 4 (MVZ); 1 mi. N Winnemucca, 4600 ft., 8 (MVZ); 5 mi. NE Golconda, 7 (MVZ); 3 mi. SW Winnemucca, 4500 ft., 1 (MVZ); 4 mi. SW Winnemucca, 4500 ft., 1 (MVZ); 5 mi. SW Winnemucca, 4600 ft., 2 (MVZ); 8 mi. E and 1 mi. N Jungo, 4200 ft., 6 (MVZ); 11 mi. E and 1 mi. N Jungo, 4200 ft., 7 (MVZ); 10 mi. SW Winnemucca, 4500 ft., 1 (MVZ); 23 mi. NW Battle Mountain, 4 (MVZ). _Pershing County_: 15 mi. SW Winnemucca, 1 (MVZ). _Lander County_: Izenhood, 2 (MVZ); 3 mi. S Izenhood, 2 (MVZ).

=Dipodomys ordii attenuatus= Bryant

_Dipodomys ordii attenuatus_ Bryant, Occas. Papers, Museum of Zool., Louisiana State Univ., no. 5:65, November 10, 1939.

_Type._--Male, no. 80429, Museum of Vertebrate Zoology, University of California; Mouth of Santa Helena Canyon, 2146 ft., Big Bend of the Rio Grande, Brewster County, Texas; obtained on November 19, 1938, by Adrey E. Borell, original no. 5581.

_Range._--Big Bend region of Brewster County, Texas.

_Diagnosis._--Size small (see measurements). Color light, entire dorsal surface between Pinkish Buff and Pinkish Cinnamon, purest on sides and flanks, upper parts but lightly mixed with black; cheeks and narrow outer margin of ear, pure white; arietiform markings absent; pinnae of ears, dorsal and ventral stripes of tail, brownish; plantar surfaces of hind feet, blackish. Skull small; rostrum long and narrow; nasals short; interparietal longer than wide; auditory bullae longer than deep.

_Comparisons._--Compared with _Dipodomys ordii ordii_, _D. o. attenuatus_ differs in: Size smaller; color lighter; skull smaller; nasals thinner; rostrum narrower; auditory bullae less inflated.

From _Dipodomys ordii richardsoni_, _D. o. attenuatus_ differs in smaller size and lighter color. Skull smaller in all respects.

For comparison with _Dipodomys ordii sennetti_ see account of that subspecies.

_Remarks._--This small race of _Dipodomys ordii_ was known formerly only from the type locality. This study has shown it to range northward and slightly westward. At four places, 6, 20, and 47 miles south of Marathon and 10 miles west of San Vicente, Texas, this race can be said to be typical, in that specimens from these places agree with those from the type locality. At two other localities, 5 miles east of Toyahvale and Kent, Texas, animals show an intergrading tendency toward _Dipodomys ordii ordii_. The animals from these latter places are darker colored and are intermediate in size and cranial characters. Since these animals show more resemblance to _D. o. ordii_ in the majority of characters they are referred to that race, rather than to _D. o. attenuatus_.

_Specimens examined._--Total, 14, all from Texas, distributed as follows: _Brewster County_: 6 mi. S Marathon, 1 (USBS); 20 mi. S Marathon, 1 (USBS); Cooper's Well, 47 mi. S Marathon, 4 (MVZ); 10