Chapter XI: Part 11

_Type._--Obtained at Glacier, British Columbia, by J. A. Loring, on
August 13, 1894; type in United States National Museum.

_Racial characters._--Similar to _bangsi_ and _columbiensis_ but
with larger feet and grayer color.

_Measurements._--Howell (1918: 49) gives the average of 10
specimens as: total length 342; length of tail 153; hind foot
41.5.

_Distribution._--The Pend Oreille Mountains of extreme
northeastern Washington, north (from records of Taylor and Shaw,
1929: 18-19, as revised) to Sullivan Lake and south to Loon Lake.

=Glaucomys sabrinus fuliginosus= (Rhoads)

_Sciuropterus alpinus fuliginosus_ Rhoads, Proc. Acad. Nat. Sci.
Philadelphia, p. 321, June, 1897.

_Glaucomys sabrinus fuliginosus_ Howell, N. Amer. Fauna, 44:47,
June 13, 1918.

_Type._--Obtained at Martin Station, Kittitas County, Washington,
by Allan Rupert in March, 1893; type in Philadelphia Academy of
Natural Sciences.

_Racial characters._--Similar to _columbiensis_ but underparts
darker and tail paler. Larger and paler than _oregonensis_.

_Measurements._--Three females from the Cascades average: total
length 327; length of tail 145; hind foot 40.7; ear 25.

_Distribution._--The Cascade Mountains, according to Taylor and
Shaw (1929: 18), as revised here, east to Entiat River and south
to Carson.

=Perognathus parvus= (Peale)

Great Basin pocket mouse

_Description._--Great Basin pocket mice are slightly larger than house mice. The ears are tiny and round; the tail is relatively long, slightly longer than the head and body; the forefeet are small but the hind feet are large and powerful, more than one-fourth as long as the head and body. They have relatively large, fur-lined, external cheek pouches. The color of the upper parts varies with the subspecies from blackish olive-gray to buffy olive-gray; a line of clear buff or buffy-olive extends along the lower part of side, separating the darker color of the upper parts from the white underparts; the tail is short-haired, blackish above, olive beneath.

Pocket mice of the genus _Perognathus_ range from Mexico northward to British Columbia. Only one species, _parvus_, occurs in Washington where it is represented by three subspecies. Pocket mice are most common in the Upper Sonoran Life-zone in sandy areas dotted with desert shrubs. They are found occasionally in dry, grassy places in the Arid Transition Life-zone. They may be locally abundant in rocky areas and are often trapped high on talus slides, many yards from the nearest soil. Gray (1943: 191-193) estimates their numbers on the sagebrush areas of the Yakima Valley at 32 per acre. They are completely nocturnal. Their ordinary movements are rather slow and specimens studied by the aid of a searchlight usually crept quietly into the protection of the nearest desert shrub. The trail of a pocket mouse in soft sand may be recognized by the distinctive mark left by the dragging tail.

Burrows of pocket mice usually are at the bases of shrubs where tough roots furnish protection. They are kept closed during the day by means of a plug of fresh earth or sand. Openings may often be recognized by a fan-shaped pile of fresh sand before the hole. Burrows excavated were usually less than four feet in length and branched from two to four times. No nests were found in the burrows but one contained a few fresh stalks of desert annuals. The air in the burrows seemed warm and humid.

The pouches of pocket mice from Washington often contain the fresh, green tips of desert plants, grass seeds, seeds of plants other than grasses, and plant leaves. Because of their occasional great abundance, pocket mice may be a menace to agriculture. Fortunately much of their habitat is unsuited to farming.

In Washington pocket mice breed in March and April. From 4 to 8 embryos were found in pregnant females.

=Perognathus parvus parvus= (Peale)

_Cricetodipus parvus_ Peale, U. S. Explor. Exped., 8 (mamm. and
ornith.):53, 1848.

_Perognathus parvus_ Cassin, U. S. Explor. Exped., 8 (mamm. and
ornith.):48, 1858.

_Perognathus parvus parvus_ Miller, Bull. U. S. Nat. Mus.,
128:278, April 29, 1924.

_Type._--Probably obtained in the neighborhood of The Dalles, Wasco
County, Oregon.

_Racial characters._--Size small; upper parts brownish-buff washed
with blackish or, in gray phase, ashy gray washed with blackish;
sides buffy yellow; a buffy spot often present on throat; tail
blackish above, olive below; facial markings usually brownish-buff
but in older animals indistinct and washed with blackish.

_Measurements._--Thirty-one males and 19 females from Washington
average, respectively: total length 169, 164; length of tail 90,
86; hind foot 22.6, 21.8; ear 5, 5.

_Distribution._--Southeastern Washington south of the Snake River,
the area on the north side of the Columbia River in Klickitat
County, and the Yakima Valley area as far north as the Vantage,
Kittitas County (W. W. D.). Other marginal records are: Kennewick
(W. W. D.), Atilla (W. W. D.) and Walla Walla (E. S. B.).

_Remarks._--Dichromatism seems to be rather common in _Perognathus
p. parvus_--so common that Osgood (1900: 35) recognized both a
"red" and a "gray" phase. Anderson (1932: 102) found no
dichromatism in _P. p. lordi_ in British Columbia. A single
specimen from the Grand Coulee at Dry Falls, Grant County, does
show dichromatism. It is even more red than the reddest topotypes
of _parvus_ examined.

Seemingly the recessive gene for red is still present in _lordi_,
or has mutated anew. When present, the color is deeper and brighter
than in the parent population, in keeping with the heavier
pigmentation of the race _lordi_.

=Perognathus parvus lordi= (Gray)

_Abromys lordi_ Gray, Proc. Zoöl. Soc. London, p. 202, 1868.

_Perognathus lordi_ Merriam, N. Amer. Fauna, 1:28, October 25,
1889.

_Perognathus lordi lordi_ Miller, U. S. Nat. Mus. Bull., 128:279,
April 29, 1924.

_Perognathus parvus lordi_ Davis, Recent Mamm. of Idaho, p. 266,
Caxton Printers, Caldwell, Idaho, April 5, 1939.

_Type._--Obtained in southern British Columbia (probably near Lake
Osoyoos) by J. K. Lord, probably in 1860.

_Racial characters._--Size large; color of upper parts
buffy-olive, washed with blackish; sides buff-olive; facial
markings absent or, if present, indistinct and pale olive; tail
blackish above, olive below.

_Measurements._--Twenty-nine males and 10 females average,
respectively: total length 175, 171; length of tail 93, 89; hind
foot 23.4, 22.9; ear 5.3, 5.1.

_Distribution._--Okanogan Valley and the Columbian Plateau, except
for the southwestern part. Marginal localities are: Vantage, Grant
County (W. W. D.), 10 mi. S. Moses Lake (W. W. D.), Washtucna (M.
V. Z.) and Pullman (M. V. Z.).

_Remarks._--There are constant differences between _Perognathus parvus parvus_ and _Perognathus parvus lordi_. The latter is larger, darker, and differs slightly in average cranial measurements. The Snake River, the Columbia River, and the Wenatchee Mountains separate the geographic ranges of the two subspecies and prevent intergradation between them. Nevertheless their close similarity and probable common origin indicate that both belong to one species, namely _parvus_.

=Perognathus parvus columbianus= Merriam

_Perognathus columbianus_ Merriam, Proc. Acad. Nat. Sci.
Philadelphia, p. 263, September 27, 1894.

_Perognathus lordi columbianus_, Osgood, N. Amer. Fauna, 18:40,
September 20, 1900.

_Type._--Obtained at Pasco, Franklin County, Washington, by Clark
P. Streator on May 9, 1891; type in United States National Museum.

_Racial characters._--Size and color as in _lordi_ but skull
considerably wider in mastoid region.

_Measurements._--Twenty-one male and 9 female topotypes average,
respectively: total length 173, 168; length of tail 91, 89; hind
foot 23.9, 22.8; ear 5, 5.

_Distribution._--The vicinity of the type locality and the part of
the Columbian Plateau north of the Snake and east of the Columbia
rivers.

_Remarks._--This race is separated from _parvus_ by river barriers and the two do not intergrade. It differs significantly from _lordi_ only in the wider mastoid region. No barrier separates the range of _lordi_ from that of _parvus_, and the two races intergrade over a wide area (north to Moses Lake, east to Washtucna). The race _columbianus_ must have originated _in situ_ from _lordi_. The habitat of _columbianus_ seems not to differ from that of _parvus_ or _lordi_.

=Dipodomys ordii columbianus= (Merriam)

Ord kangaroo rat

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

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

_Type._--Obtained at Umatilla, Umatilla County, Oregon, by C. P.
Streator on October 18, 1890; type in United States National
Museum.

_Measurements._--Fourteen males and 9 females from Walla Walla
County average, respectively: total length 261.5, 248.4; length of
tail 137.2, 139.1; hind foot 40.6, 40.8; ear 13.1, 13.0; weight
52.1, 49.0 grams.

_Distribution._--Western Walla Walla County from the Oregon
boundary north to the Snake River and on Blalock Island in the
Columbia River, Benton County.

_Description._--The kangaroo rat with a body about the size of that of a chipmunk has an exceptionally large head and large, black eyes. The forelegs and forefeet are tiny but the hind feet and legs are large and powerful. The hind foot is almost a third as long as the head and body. The tail is long, longer than the head and body. Kangaroo rats possess fur-lined, external cheek pouches, like those of the pocket mice. The upper parts are soft buff in color. The underparts and a stripe on each flank are white. The tail is dusky above and below, with white sides; it is tufted at the tip.

Kangaroo rats are typical of the desert regions of the southwestern United States, where numerous species and subspecies are found. A single subspecies of the wide-ranging species _ordii_ occurs into southeastern Washington, where it is restricted to sandy areas in the Upper Sonoran Life-zone. In the soft, drifted sand along the Columbia River where sagebrush and other desert shrubs are low and widely spaced kangaroo rats are abundant.

These rats are strictly nocturnal. When individuals are dug from their burrows in the daytime they usually hop about in a dazed manner and appear to be blinded by sunlight. Near Wallula, Walla Walla County, these rats were caught at night with a butterfly net as they stood "paralyzed" in the beam of a powerful searchlight. Such night hunting was unsuccessful on cloudy or windy nights when kangaroo rats seem not to move about.

As might be guessed from their powerful hind legs, kangaroo rats travel in bounds. Near Wallula, where we watched them in their natural habitat, they traveled, when unfrightened, in slow hops, each hop followed by a pause. As they struck the surface of the ground an audible thud could be heard for a distance of several feet. After each jump they paused for a second or so, perhaps to allow a pursuing enemy to over-run them.

Near Wallula the burrows of kangaroo rats were dug in large mounds of wind-blown sand. The burrows entered these natural mounds horizontally and branched two or three times. Their average length was about five feet. No nests or food stores were discovered although several kangaroo rats were caught as they burst from entrances at sides of the mounds. All entrances to burrows were plugged with soft sand. The air in the burrows seemed warm and humid.

Food found in the cheek pouches of kangaroo rats from Washington included the seeds of desert annuals, short sections of sprouts of an unidentified plant, grass seeds, and the leaves of the hop-sage.

A female taken March 22, 1939, contained 3 embryos.

=Thomomys talpoides= (Richardson)

Northern pocket gopher

_Description._--The pocket gopher is a fossorial animal, being but slightly less adapted to an underground existence than the moles. The body is stout, the legs short and the head broad. The tail is short, sparsely haired, cylindrical and blunt-ended. The fur is soft and dense. The eyes are small and the ears tiny and naked. The incisor teeth are external, being separated from the mouth cavity by a furry strip of skin. Like the pocket mouse and kangaroo rat, the pocket gopher possesses external, fur-lined cheek pouches. The openings of these begin just below and posterior to the nostrils, sweep out and down in a semicircle, and end at the chin posterior to the base of the lower incisors. They extend laterally to the shoulders and easily accommodate a fifty-cent piece.

The family Geomyidae is composed of eight genera, so similar in appearance that the name "pocket gopher" is applied to all of them. The family is confined to North and Central America. Three genera occur in the United States but only one, _Thomomys_, occurs in Washington. _Thomomys_ is restricted to western North America where it ranges from central Canada south to the southern edge of the table land of Mexico.

Several hundred kinds of _Thomomys_ have been described and as systematic work with this genus has been continued, more and more kinds, originally thought to be species, are found to intergrade and to be only subspecies. All of the 17 kinds of pocket gophers occurring in Washington belong to a single species.

The pocket gopher is principally nocturnal or crepuscular but sometimes it is active at midday, especially if the day be dark and cloudy. Pocket-gopher activity is indicated by fresh mounds of earth on the surface of the ground. Rarely, an observer may see movement of plants as the gopher molests the roots of the plants, or even see the head and shoulders of an animal that partly emerges from an open burrow. The ordinary gopher mound consists of less than a cubic foot of earth. The earth is forced up from a single opening and usually is pushed out in one direction. In consequence it forms in a fan-shaped pile about the opening, and the last load forms a circular plug above and to one side of the burrow opening. When so much earth has been forced out of one opening that expulsion of additional loads of earth is overly difficult, the burrow is extended slightly to one side, or even extended into the newly formed mound, and another fan formed. Usually not more than three coalesced fans form a mound, but where the soil is exceedingly soft and fluffy, hundreds of fans may form a composite mound and the one mound may include a cubic yard of earth. Large composite mounds probably are formed gradually over a period of weeks or even months.

The earth in a fresh gopher mound is usually "scratched," and gives the appearance of having been sieved. Pebbles weighing more than 100 grams are included in material ejected from burrows. The entrances to the burrows of gophers are usually solidly plugged with earth. The plug may be from a few inches to more than a foot in length. At times a burrow entrance may appear to be open, but in such cases investigation will usually reveal it to be plugged some distance back--sometimes several feet.

In contrast to the gopher mounds described above, the mounds of moles are not fan-shaped but volcano-shaped. The earth from a mole's burrow is forced straight upwards, whence it falls to either side. Later loads are pushed up from beneath, raising the entire mound, with the last material ejected at the center and bottom. The earth of a fresh mole-mound is not of fine texture but instead is "clotted" and, if damp, gives the mound a fractured appearance. When mounds are older, perhaps changed by rain and sun, their identity as of mole-origin or pocket gopher-origin is more difficult to establish. In such cases, if no fresh mounds can be found, the observer must rely on the spacing of the mounds. Mole-mounds are spaced along a burrow, about as far apart as a man can step. Gopher mounds are irregularly spaced, and the course of the burrow cannot be traced merely by observing the arrangement of the mounds as can that of the mole.

In addition to mounds, gopher burrows have plugged openings where a gopher has come to the surface, probably to cut plants. Such entrances are marked by a plug of earth several inches long. Mounds and feeding entrances of the gopher burrow are usually not constructed in the main burrow system itself, but at the ends of lateral burrows of varying length. If one traces the burrow back from the mound, a junction with the main, better-constructed burrow is found. The junction is usually T-shaped, with the lateral burrow at right angles to the main burrow. More rarely the junction has a Y-shape.

The burrow system of the pocket gopher may be divided into three main parts. These are the laterals, just discussed, the main burrow, and the deep nesting burrow. The main burrow is a sinuous tube or tunnel at a relatively uniform depth, that marks the extent of the gopher's home territory. This tunnel may branch, or even intersect. As it is extended in one direction, the earth excavated by the gopher may in part be thrust into an unused portion of the burrow.

The deep, nesting burrows may be used only in the breeding season. They are connected with the main tunnel system but descend to a greater depth. Usually they descend into the harder, consolidated layers of soil below the zone where plant roots penetrate. Here chambers are constructed in which nests and food are stored. Usually a vertical shaft is dug in the burrow ahead of the nest to lead rain water away from the nest.

In areas where gophers live in a thin layer of soil underlain by a more or less impenetrable layer of rock, clay or gravel, it has been suggested that they form unique structures known as Mima Mounds. The formation of these mounds has been discussed in detail elsewhere (Dalquest and Scheffer, 1942: 68-84). At least in the breeding season the gophers work mainly and make their nest where the soil is deepest. In the vicinity of this nest, considerable mounding and cultivation of soil ensues. This stimulates plant growth in the area. Much observation indicates that cultivation of earth by gophers stimulates plant growth to a greater extent than the depredations of the gopher deplete the ensuing growth. Thus the gopher, by cultivation of the soil in the area about its burrow, stimulates the growth of vegetation and so increases his own food supply. Consequently there is but little incentive for the gopher to leave the vicinity of the nest. The gopher does, however, construct lateral tunnels into surrounding areas. Earth from these lateral tunnels is, in part, thrown to the surface in mounds and in part transported back to fill the abandoned burrows near the nest. The earth from the burrows about the nest was earlier ejected on the surface. Slowly, then, earth is transported from surrounding areas to burrows in the vicinity of the original nest. Each succeeding generation finds in the vicinity of the original nest, better food and deeper soil, while areas surrounding the nest possess thinner soil and less vegetation. Over a period of thousands of generations of gophers, large mounds, known as Mima Mounds, are formed. Since the removal of earth from the surrounding areas and its accumulation in the Mima Mound are chance affairs, the contours of the mound are smooth and flowing while the contours of the intermound areas are smoothly convex.

The pocket gophers in Washington are economically important. In truck and flower gardens they are a pest, especially if the crop be bulb plants. In grain fields they are a pest because their mounds cover considerable grain and are apt to clog or dull the knife of the mower. In fields of young alfalfa they are apt to crop back the plant more rapidly than it can grow. Once the alfalfa plant is well established, however, the cultivation resulting from activities of gophers, some persons believe, stimulates the plant to such an extent that it grows larger and healthier in spite of the gopher's feeding on it. In the White Salmon Valley, Klickitat County, I examined numerous alfalfa fields. The most luxuriant growth was invariably in fields where gophers were common. In these fields, the largest plants were those in the immediate vicinity of gopher activity. The commensal relation between the gopher and alfalfa was understood by many farmers, who forbade us to take gophers for specimens from their fields. Several told us that they always trapped the gophers from the fields of young alfalfa and from hay meadows but encouraged their presence in fields of older alfalfa.

Another economic factor is the gopher's removal of certain weeds from grazing land. A number of introduced weeds form dense rosettes that prevent the growth of grass from several square inches of ground and themselves lie so close to the ground as to be unavailable as food to grazing stock. These weeds seem to be favored food of gophers which cut not only the rosettes but the roots of the weeds as well.

In irrigated parts of eastern Washington the gopher is a serious pest. It burrows in the banks of the main ditches, causing cave-ins and occasional breaks with resultant water loss. The mounds of gophers fill in the smaller channels and divert the streams. Constant attention is necessary to keep the ditches free of gopher mounds.

In uncultivated land the gopher is a distinct asset unless the land is near enough to cultivated land to serve as a reservoir of pests. In the mountains and on the desert the gopher cultivates and keeps the soil soft and stimulates the growth of water-retaining vegetation, thus preventing rapid run-off and erosion and keeping the flow of springs and streams constant. Boulders, logs, and other obstructions are undermined and, as a result of gopher activity, in time sink under the surface of the ground. Thus a larger surface is available for plant growth. Lastly the gopher furnishes an important food source for certain fur-bearing mammals and eases the predator pressure on game species.

The subspecies of pocket gopher occupying the Puget Sound area are highly restricted in their habitat preference; they occur only on the grassy prairies of the glacial outwash aprons. They do not occur in woods, brush or even small openings on the borders of the prairies. The alpine forms occupy the mountain meadows and are slightly less selective in their habits. It should be noted that in western Washington the forests are far more open at higher altitudes than at low elevations. The races inhabiting the desert are found in open areas, often in sandy places. They occur more rarely in areas where the soil is baked and claylike, and then usually in the vicinity of springs or watercourses. The race _T. t. fuscus_ has a wide range of tolerance as regards environmental factors; it occurs near Wenatchee in essentially desert conditions, in alpine meadows of northeastern Washington, and in many habitats at intermediate elevations. It occurs also in brushy areas and is often abundant in open pine forests.

Since the gopher usually has a narrow range of tolerance as regards its environmental adaptations, this has resulted in considerably more isolation than is the case with other mammals, and has probably contributed to the formation of the many subspecies. Within the range of almost every race, microgeographic races, or local populations with distinctive characters, are found. Many subspecies of _Thomomys_ are probably the result of chance fixation of genetic characters already present in a more genetically variable ancestral population, and the loss of other genetic factors. Such races might be considered degenerative (see Dalquest and Scheffer, 1944: 24).

The history of the pocket gophers of Washington has been traced previously (Dalquest and Scheffer, 1942, 1944). It may be briefly summarized as follows: At the close of Vashon-Wisconsin times, gophers were found in the southern Cascades, on the Simcoe Bridge, the Columbian Plateau, and in southeastern Washington. Following the retreat of the ice, the gophers in the Mount Rainier area spread westward on the outwash of the Nisqually and perhaps other glaciers to the Vashon Outwash about southern Puget Sound and thence to the Olympic Mountains. In the southern Cascades, gophers spread westward on glacial terraces of the Columbia River to the vicinity of Vancouver, Clark County. The establishment and growth of the forests split up the original populations, and continued spread of forest has exterminated many units. All the races in the lowlands of western Washington face extermination as the prairies are reclaimed by forest.

Pocket gophers also invaded northeastern Washington from Idaho and spread westward to the Cascades, thence southward until the native gophers were encountered north of Mount Rainier and in the Yakima Valley. The invading gophers nearly surrounded the Columbian Plateau.

T. H. Scheffer (1938B: 220-224) found the gestation period of the pocket gopher to be approximately 28 days. No second brood is raised in Washington. Near Kennewick, Yakima County, the young are born from February to April. The average number of embryos found in 76 female gophers was 6.3. Near Olympia, Thurston County, the young are born from March to June. The average number of embryos from 312 females was 5.0.

=Thomomys talpoides devexus= Hall and Dalquest

_Thomomys talpoides devexus_ Hall and Dalquest, Murrelet, 20:3,
April 30, 1939.

_Thomomys talpoides ericaeus_ Goldman, Jour. Mamm., 20:243, May
15, 1939 (type from Badger Mountains, Douglas County, Washington).

_Type._--Obtained 1 mile west-southwest of Neppel (now Moses Lake),
Grant County, Washington, by W. W. Dalquest on May 30, 1938; type
in Museum of Vertebrate Zoölogy.

_Racial characters._--Size medium; ears tiny; color of upper parts
pale brownish gray; underparts white; postauricular spots dark.

_Measurements._--Two male and 4 female topotypes average,
respectively: total length 184, 184; length of tail 54, 55; hind
foot 25, 25; weight 89, 71 grams.

_Distribution._--The Columbian Plateau. Marginal occurrences of
the races of pocket gophers occurring in Washington are not listed
here because they have recently been placed on record (Dalquest
and Scheffer, 1944: 308-333, 423-450).

_Remarks._--This is the smallest and palest race of pocket gopher found in Washington.

=Thomomys talpoides columbianus= Bailey

_Thomomys fuscus columbianus_ Bailey, Proc. Biol. Soc. Washington,
27:117, July 10, 1914.

_Thomomys columbianus_ Bailey, N. Amer. Fauna, 39:106, November
15, 1915.

_Thomomys talpoides columbianus_ Goldman, Jour. Mamm., 20:234, May
15, 1939.

_Type._--Obtained at Touchet, Walla Walla County, Washington, by C.
P. Streator on September 10, 1890; type in United States National
Museum.

_Racial characters._--Larger and brighter in color than _devexus_.
Near ochraceous orange in color.

_Measurements._--Five male and three female topotypes average,
respectively: total length 213, 209; length of tail 60, 58; hind
foot 29, 28.

_Distribution._--Walla Walla County, between the Snake River and
the Oregon boundary and from the Columbia River east to the
Columbia County line.

=Thomomys talpoides aequalidens= Dalquest

_Thomomys talpoides aequalidens_ Dalquest, Murrelet, 23:3, May 14,
1942.

_Type._--Obtained at Abel Place, 2,200 ft., 6 miles south-southeast
of Dayton, Columbia County, Washington, by S. H. Lyman, on April 6,
1934; type in Museum of Vertebrate Zoölogy.

_Racial characters._--Large size, very dark color.

_Measurements._--The average of four male topotypes and the
measurements of one female topotype are, respectively: total
length 202, 201; length of tail 57, 59; hind foot 26, 27.

_Distribution._--Southeastern Washington east of the range of
_columbianus_ and north of the higher parts of the Blue Mountains.

=Thomomys talpoides wallowa= Hall and Orr

_Thomomys quadratus wallowa_ Hall and Orr, Proc. Biol. Soc.
Washington, 46:41, March 24, 1933.

_Thomomys talpoides wallowa_ Goldman, Jour. Mamm., 20:234, May 15,
1939.

_Type._--Obtained at Catherine Creek, 7 miles east of Telocaset,
3,500 ft., Union County, Oregon, by R. T. Orr on June 29, 1932;
type in Museum of Vertebrate Zoölogy.

_Racial characters._--Similar to _devexus_ but much darker.
Similar (in Washington) to _aequalidens_ but much smaller.

_Measurements._--Four males and 4 females from Mountain Top and
Stay-a-while Spring, Columbia County, average, respectively: total
length 191, 180; length of tail 56, 52; hind foot 26, 25.

_Distribution._--The higher parts of the Blue Mountains.

_Remarks._--Washington specimens referred to this race are intermediate between _wallowa_ and _aequalidens_ but are colored like _aequalidens_.

=Thomomys talpoides fuscus= Merriam

_Thomomys clusius fuscus_ Merriam, N. Amer. Fauna, 5:69, July 30,
1891.

_Thomomys myops_ Merriam, Proc. Biol. Soc. Washington, 14:112,
July 19, 1901 (type from Conconnully, Okanogan County,
Washington).

_Thomomys fuscus fuscus_ Bailey, N. Amer. Fauna, 39:126, November
15, 1915.

_Thomomys talpoides fuscus_ Hall and Dalquest, Murrelet, 20:4,
April 30, 1939.

_Type._--Obtained at the head of Big Lost River, Custer County,
Idaho, by B. H. Dutcher on September 23, 1890; type in United
States National Museum.

_Racial characters._--Similar to _devexus_ but upper parts rich
tawny in color.

_Measurements._--Three males and 2 females from Newport, Pend
Oreille County, average, respectively: total length 189, 186;
length of tail 54, 57; hind foot 27, 26.

_Distribution._--Along the eastern border of the state to the
north of the Snake River, northeastern Washington, and the
northeastern Cascades.

=Thomomys talpoides yakimensis= Hall and Dalquest

_Thomomys talpoides yakimensis_ Hall and Dalquest, Murrelet, 20:4,
April 30, 1939.

_Thomomys talpoides badius_ Goldman, Jour. Mamm., 20:242, May 15,
1939 (type from Wenatchee, Chelan County, Washington).

_Type._--Obtained at Selah, Yakima County, Washington, by P.
Burgner, on November 27, 1938; type in Museum of Vertebrate
Zoölogy.

_Racial characters._--Similar to _fuscus_ but more orange, less
red.

_Measurements._--Four male and 3 female topotypes average,
respectively: total length 209, 191; length of tail 60, 56; hind
foot 27, 26.

_Distribution._--The eastern edge of the Cascades from the
Wenatchee Mountains south to the Simcoe Anticline.

=Thomomys talpoides shawi= Taylor

_Thomomys douglasii shawi_ Taylor, Proc. Biol. Soc. Washington,
34:121, June 30, 1921.

_Thomomys talpoides shawi_ Hall and Dalquest, Murrelet, 20:4,
April 30, 1939.

_Type._--Obtained at Owyhigh Lakes, Mount Rainier, Pierce County,
Washington, by G. G. Cantwell, on August 9, 1919; type in United
States National Museum.

_Racial characters._--A large, tan-colored pocket gopher, similar
to _aequalidens_ but paler.

_Measurements._--Two male and 7 female topotypes average,
respectively: total length 227, 213; length of tail 72, 64; hind
foot 32, 30.

_Distribution._--The higher Cascade Mountains from Mount Rainier
southward. Southern limits of range unknown.

=Thomomys talpoides immunis= Hall and Dalquest

_Thomomys talpoides immunis_ Hall and Dalquest, Murrelet, 20:4,
April 30, 1939.

_Type._--Obtained 5 miles south of Trout Lake, Klickitat County,
Washington, by W. W. Dalquest on July 27, 1937; type in Museum of
Vertebrate Zoölogy.

_Racial characters._--Similar to _shawi_ but paler and grayer.

_Measurements._--Two males and 2 females from Morrison Springs
Ranger Station, Skamania County, average, respectively: total
length 211, 212; length of tail 64, 58; hind foot 28, 29.

_Distribution._--The Cascade Mountains from the vicinity of Mount
Adams north. The zone of intergradation between _shawi_ and
_immunis_ is in the rugged, inaccessible mountains between Mount
Rainier and Mount Adams.

=Thomomys talpoides limosus= Merriam

_Thomomys limosus_ Merriam, Proc. Biol. Soc. Washington, 14:116,
July 19, 1901.

_Thomomys talpoides limosus_ Goldman, Jour. Mamm., 20:235, May 15,
1939.

_Type._--Obtained at White Salmon, Klickitat County, Washington, by
J. A. Loring on June 26, 1897; type in United States National
Museum.

_Racial characters._--Similar to _immunis_ but darker with
smaller, shorter skull.

_Measurements._--One male and 13 female topotypes average,
respectively: total length 210, 198; length of tail 55, 56; hind
foot 30, 28.

_Distribution._--The lower Columbia River Valley, from the type
locality east to the Columbian Plateau.

=Thomomys talpoides douglasii= (Richardson)

_Geomys douglasii_ Richardson, Fauna Boreali-American, 1:200, 1829.

_Geomys fuliginosus_ Schinz, Syn. Mamm., 2:136, 1846 (type from
"Habitat ad fluvium Columbia").

_Thomomys douglasii_ Allen, Bull. Amer. Mus. Nat. Hist., 5:66,
April 28, 1893.

_Thomomys douglasi douglasi_ Bailey, N. Amer. Fauna, 39:116,
November 15, 1915.

_Thomomys talpoides douglasii_ Goldman, Jour. Mamm., 20:234, May
15, 1939.

_Type._--Obtained at Fort Vancouver (now the city of Vancouver),
Clark County, Washington, by David Douglas, probably in 1825.
Probably not now in existence.

_Racial characters._--A medium-sized, yellowish gopher with tiny,
pointed ears and very small postauricular patches.

_Measurements._--Two male and 10 female topotypes average,
respectively: total length 227, 213; length of tail 68, 63; hind
foot 30, 30; and weight 148, 117 grams.

_Distribution._--Known only from Clark County.

=Thomomys talpoides glacialis= Dalquest and Scheffer

_Thomomys talpoides glacialis_ Dalquest and Scheffer, Proc. Biol.
Soc. Washington, 55:97, August 13, 1942.

_Type._--Obtained 2 miles south of Roy, Pierce County, Washington,
by W. W. Dalquest, on December 19, 1941; type in United States
National Museum.

_Racial characters._--A dark, yellowish-brown gopher with
orange-tinged underparts.

_Measurements._--Twenty male and 17 female topotypes average,
respectively: total length 225, 220; length of tail 72, 71; hind
foot 30, 30; and weight 128, 116 grams.

_Distribution._--Known only from Roy Prairie, Pierce County.

=Thomomys talpoides tacomensis= Taylor

_Thomomys douglasii tacomensis_ Taylor, Proc. Biol. Soc.
Washington, 32:169, September 30, 1919.

_Thomomys talpoides tacomensis_ Goldman, Jour. Mamm., 20:235, May
15, 1939.

_Type._--Obtained 6 miles south of Tacoma, Pierce County,
Washington, by G. G. Cantwell on December 24, 1918; type in United
States National Museum.

_Racial characters._--A large, dark form; rich hazel in color with
large, black postauricular patches and ochraceous underparts.

_Measurements._--Thirteen male and 15 female topotypes average,
respectively: total length 224, 196; length of tail 71, 57; hind
foot 31, 29; and weight 127, 104 grams.

_Distribution._--Restricted to the area about Steilacoom and
Tacoma, Pierce County, Washington.

=Thomomys talpoides pugetensis= Dalquest and Scheffer

_Thomomys talpoides pugetensis_ Dalquest and Scheffer, Proc. Biol.
Soc. Washington, 55:96, August 13, 1942.

_Type._--Obtained 4 miles south of Olympia, Thurston County,
Washington, by W. W. Dalquest, on December 31, 1941; type in United
States National Museum.

_Racial characters._--Similar to _glacialis_ but underparts not
tinged with orange and conspicuous dusky areas present on sides of
neck.

_Measurements._--Fourteen male and 19 female topotypes average,
respectively: total length 223, 205; length of tail 62, 59; hind
foot 30, 29; and weight 123, 96 grams.

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

=Thomomys talpoides tumuli= Dalquest and Scheffer

_Thomomys talpoides tumuli_ Dalquest and Scheffer, Proc. Biol. Soc.
Washington, 55:96, August 13, 1942.

_Type._--Obtained on Rocky Prairie, 7 miles north of Tenino,
Thurston County, Washington, by W. W. Dalquest on January 2, 1942;
type in United States National Museum.

_Racial characters._--Similar to _pugetensis_ but grayer, less
yellow.

_Measurements._--Eleven male and 14 female topotypes average,
respectively: total length 225, 216; length of tail 60, 64; hind
foot 31, 30; and weight 140, 118 grams.

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

=Thomomys talpoides yelmensis= Merriam

_Thomomys douglasi yelmensis_ Merriam, Proc. Biol. Soc. Washington,
13:21, January 31, 1899.

_Thomomys douglasii yelmensis_ Taylor, Proc. Biol. Soc.
Washington, 32:169, September 30, 1919.

_Thomomys talpoides yelmensis_ Goldman, Jour. Mamm., 20:235, May
15, 1939.

_Type._--Obtained at Tenino, Thurston County, Washington, by C. P.
Streator on October 24, 1891; type in United States National
Museum.

_Racial characters._--A rather small, yellowish race with whitish
underparts.

_Measurements._--Twenty-one male and 21 female topotypes average,
respectively; total length 213, 202; length of tail 64, 61; hind
foot 29, 28; and weight 121, 101 grams.

_Distribution._--Known only from Grand Mound Prairie (type
locality), Vail Prairie, near Vail, and Rochester Prairie, near
Rochester, all in Thurston County.

=Thomomys talpoides couchi= Goldman

_Thomomys talpoides couchi_ Goldman, Jour. Mamm., 20:243, May 15,
1939.

_Type._--Obtained on Scotts Prairie, 4 miles north of Shelton,
Mason County, Washington, by L. K. Couch, on June 27, 1922; type in
United States National Museum.

_Racial characters._--A small race; rich hazel in color.

_Measurements._--Thirteen male and 9 female topotypes average,
respectively: total length 196, 191; length of tail 55, 53; hind
foot 27, 27; and weight 87, 79 grams.

_Distribution._--Known only from the type locality and from Lost
Lake Prairie, near Satsop, Mason County.

=Thomomys talpoides melanops= Merriam

_Thomomys melanops_ Merriam, Proc. Biol. Soc. Washington, 13:21,
January 31, 1899.

_Thomomys douglasi melanops_ Bailey, N. Amer. Fauna, 39:119,
November 15, 1915.

_Thomomys talpoides melanops_ Goldman, Jour. Mamm., 20:235, May
15, 1939.

_Type._--Obtained at head of Sol Duc River, Clallam County,
Washington, by V. Bailey on August 28, 1897; type in United States
National Museum.

_Racial characters._--Most like _shawi_ but smaller, with larger
postauricular patches and dusky areas on side of head.

_Measurements._--A male topotype measures: total length 211;
length of tail 67; hind foot 28.

_Distribution._--Higher Olympic Mountains.

=Castor canadensis= Kuhl

Beaver

_Description._--The beaver is the largest rodent occurring in Washington. Large individuals weight approximately 50 pounds. They are heavily-built, robust animals with large heads and short necks. The large, flat, naked tail immediately separates them from all other mammals occurring in the state. The forelegs are short and the forefeet handlike. The hind legs are long, thick and powerful. The hind feet are large and webbed for swimming. The ears are small and the eyes, although of moderate size, are not prominent. The incisors are large and prominent with a distinct yellow or orange color. The close, dense underfur is overlaid with long, lax, rather stiff overfur or guardhairs.

Beavers are found in Europe, Asia and North America. In America they range from Alaska to Mexico and from the Atlantic to the Pacific. Many American subspecies have been described, all thought to belong to a single species.

Beavers live in streams and lakes of Washington under diverse climatic conditions. They are perhaps most abundant in the western Washington lowlands where there are numerous watercourses. In the Cascade Mountains they are found well up into the Canadian Life-zone, where the streams are swift and clear with stony bottoms. The highest altitudinal record known to us is Reflection Lake, Mt. Rainier, 4,861 feet (Brockman, 1939: 71). Farther east, in the timbered regions of the eastern Cascades and in northeastern Washington, beavers live in deeper, more sluggish streams. Abundant beaver signs were noted at the junction of the Snake and Columbia rivers where the animals were occupying one of the hottest, most desertlike portions of the state. They are found in Moses Lake, in the center of the arid Columbian Plateau. Beavers once occurred in the San Juan Islands and have recently been reintroduced there.

The part the beaver played in man's exploration of the state of Washington is a story in itself. The establishment of Fort Vancouver and Fort Spokane and other settlements was principally due to the trade in beaver pelts. These forts served as headquarters for Douglas, Suckley, Townsend, Nuttall and other early naturalists who contributed so greatly to the knowledge of the mammalian fauna of the western United States.

Trapping for fur drastically reduced the number of beavers in Washington. After trapping was prohibited they were slow in recovering and, until about 1930, they were uncommon. After that date they seemed to increase rapidly, becoming abundant about 1940. The present system of removing beavers only from areas where they are doing damage, and then only under strict supervision from the State Department of Game, has held their numbers at a high level.

The food of the beaver varies greatly with locality. Along the Columbia River, in eastern Washington, cottonwood (_Populus hastata_) and willow (_Salix_ sp.) seem to constitute favorite foods. Few other trees grow in this arid region. On Puget Island, near the mouth of the Columbia, willow, alder (_Alnus oregonus_) and probably other shrubs are eaten. In the many streams that run from the western Cascade Mountains to Puget Sound, various species of willow seem to be the principal food eaten. Some alder, cascara, Douglas fir, red huckleberry and salmonberry are eaten. In some streams on the eastern slope of the Cascades, coniferous trees, including Douglas fir, yellow pine (_Pinus ponderosa_), and red cedar (_Thuja plicata_) are used.

Beaver dams are abundant in certain sections of Washington, notably the area between the Cascade Mountains and Puget Sound. Dams several hundred feet in length were seen in the valley of Cherry Creek, 7 miles northeast of Duvall, King County. However, in most parts of the state few dams are built. No dams are necessary in the larger streams and lakes while the smaller mountain streams possess a gradient too steep for successful damming. Spring floods and high water following rains would destroy such dams.

True beaver houses, or lodges, are seldom seen in Washington. In the larger streams, rivers and lakes the beavers are "bank beavers," living in burrows with underwater entrances. In the mountain streams, log jams furnish protection. Great piles of logs and debris accumulate at bends of streams in periods of high water. These jams commonly contain large, well-anchored key logs and persist for years. Back-cutting by the stream often forms deep pools before the jams while the sloping bank opposite may support willows and alders. Thus beavers may find a home, food, and a protecting pool of deep water at a log jam. In periods of low water, and when meandering of the stream causes it to leave the log jam, canals are constructed by the beavers to connect the log jam with the stream.

Where dams are built a few lodges may occur. For the most part, however, the beavers dig holes in the bank or in small islands that result from their dam-building activities. Burrows are occasionally easy to locate because of the mud and sticks laid on the ground above. At best these sticks form a layer only a few inches thick and are too loosely packed to furnish any additional protection. They probably represent a concession to the beavers' lodge-building instincts.

The beaver probably breeds in January. A specimen from Cle Elum, taken on March 1, contained 4 embryos and one from the Teanaway River near Cle Elum held 2 embryos on February 28. One from Swauk Creek, Kittitas County, on the eastern slope of the Cascades, had 3 embryos on February 12. A young beaver was born to a captive animal on May 18. Its mother was taken at Soos Creek in southeastern King County. This baby weighed 884 grams.

The majority of the beavers trapped are small animals, measuring from 725 to 900 mm. (total length) in February, and weighing from 10 to 20 pounds. These are kits, probably one and two years old. It is rather difficult to divide these animals into two age groups but probably the first year young (7 to 11 months old) weigh from 10 to 15 pounds and measure between 725 and 800 mm. in total length. Two-year olds (19 to 23 months) measure from 800 to 925 mm. and weigh from 15 to 25 pounds. They measure approximately 1050 mm. the third year, when they become adult, and weigh in the neighborhood of 45 pounds. Individuals occasionally weigh more than 50 pounds; these are probably old adults.

Damage by beavers is limited. Their dams occasionally flood roads and rarely fields. In some parts of eastern Washington, where fruit raising is an important industry, an individual beaver may cause considerable damage by cutting valuable trees. Ornamental trees may be damaged near the larger cities. Beavers living in Lake Washington in almost the center of the city of Seattle, caused some damage to ornamental trees on the University of Washington Golf Course. Canals and dams in small streams and ditches in areas where stock raising is practiced, flood stock food and sometimes form mudholes or bogs where stock might be trapped. Where individual beavers are doing damage they are trapped and killed, or are live-trapped and transported to more favorable habitats. In places where any beaver may be potentially dangerous, as in the fruit-growing areas of eastern Washington or stock-raising areas in western Washington, their numbers should be kept down by continued trapping.

Probably the greatest value of beavers lies in the impounding of water by their dams. This is especially true in the arid mountains of eastern Washington and in the logged-off or burned-over parts of western Washington. These ponds prevent erosion, raise the water table and so stimulate the growth of vegetation, insure greater regularity of stream flow, provide suitable water for trout and muskrats as well as some breeding grounds for waterfowl. On burned-over or logged-off land, the greatest, and often the only, growth of new conifers is in the vicinity of beaver ponds. In the vicinity of beaver dams, rich growths of willows and other deciduous vegetation provides food and cover for deer and fur-bearing mammals.

Trapping of beaver for their fur at present is not a private enterprise but controlled trapping by the state adds to public funds.

=Castor canadensis leucodonta= Gray

_Castor canadensis leucodonta_ Gray, Ann. and Mag. Nat. Hist., 4
(ser. 4):293, October, 1869.

_Castor canadensis pacificus_ Rhoads, Trans. Amer. Philos. Soc.,
19 (n. s.):422, September, 1898 (type from Lake Keechelus,
Kittitas County, Washington).

_Type._--Obtained by Dr. Robert Brown, probably on Vancouver
Island, British Columbia.

_Racial characters._--Large size; reddish color; elongate skull.

_Distribution._--Found over all but the southwestern corner of the
state. The most westward locality from which specimens have been
examined is Lake Crescent (U. S. N. M.).

_Remarks._--The good series of beaver skulls available from several areas of Washington has led to careful comparison of Washington material with specimens from Vancouver Island. Skulls from extreme southwestern Washington are small and decidedly short, being referable to the race _idoneus_. No satisfactory way of distinguishing between the others could be found and all are consequently referred to the earliest named form, _leucodonta_.

=Castor canadensis idoneus= Jewett and Hall

_Castor canadensis idoneus_ Jewett and Hall, Jour. Mamm., 21:87,
February 15, 1940.

_Type._--Obtained at Foley Creek, tributary to Nehalem River,
Tillamook County, Oregon, by C. Leach on December 15, 1914; type in
California Museum of Vertebrate Zoölogy.

_Description._--Similar to _leucodonta_ but smaller, darker, with
shorter and wider skull.

_Distribution._--Lowlands near the mouth of the Columbia River.
Specimens from Puget Island (U. S. N. M.) have been examined.

=Onychomys leucogaster fuscogriseus= Anthony

Northern grasshopper mouse

_Onychomys leucogaster fuscogriseus_ Anthony, Bull. Amer. Mus. Nat.
Hist., 32: 11, March 7, 1913.

_Type._--Obtained at Ironside, Malheur County, Oregon, by H. E.
Anthony, in 1912; type in American Museum of Natural History.

_Measurements._--Nine males and 5 females from Franklin, Benton,
and Walla Walla counties, Washington, average, respectively: total
length 132.3, 133.0; length of tail 35.8, 35.6; hind foot 19.2,
19.6; ear 17.6, 17.6; weight 23.3, 24.1 grams.

_Distribution._--The Columbian Plateau, southeastern Washington,
and the Yakima Valley, ranging north to Douglas (Taylor and Shaw,
1929: 21), west to Yakima (M. V. Z.), east to Asotin (Taylor and
Shaw, 1929: 21) and south to Wallula (Taylor and Shaw, 1929: 21).

_Description._--A mature grasshopper mouse is slightly larger than a house mouse; the head and body measure about 4 inches and the tail about 1-1/4 inches; it may be recognized by the rather plump body, naked ears, short, thick and tapering tail and soft, dense fur. The upper parts of adults are buffy. Younger animals are blue-gray above. Underparts and tail are white.

Grasshopper mice of two species range over much of northern Mexico and the western United States. The species occurring in Washington, _leucogaster_, is found from southern Manitoba to northern Mexico, and from the Pacific states east to North Dakota. This species is characteristic of the Upper Sonoran Life-zone, and usually is associated with sagebrush and greasewood. It prefers open areas of sand and avoids heavy cover, and seems to be strictly nocturnal. It eats vegetation, seeds, insects, or the flesh of other mice. According to Bailey (1936: 178), grasshopper mice pursue, catch and kill other mice. They hunt by scent and follow tracks like a wolf. They make a sound, or "call," like a miniature wolf howl. They are said to be rather docile and make friends with humans quickly.

On some occasions grasshopper mice are locally abundant, but for the most part they are rather uncommon over their range. Usually one is taken in about 200 traps set in suitable habitats. They do not hibernate; one was caught at Moses Lake, Grant County, on a freezing winter night.

The grasshopper mouse is almost always associated with the pocket mouse (_Perognathus parvus_), deer-mouse (_Peromyscus maniculatus_), and often the harvest mouse (_Reithrodontomys megalotis_). The same snakes, owls, and carnivorous mammals that prey on these mice doubtless eat also the grasshopper mouse.

R. D. Svihla (1936: 172) determined the gestation period of 3 lactating grasshopper mice captured at Lind, Adams County, as 33, 39 and 47 days. A non-lactating female gave birth to a litter in 32 days. Young varied from 2 to 5 in number and were pink and hairless at birth, with eyes and ears closed.

=Reithrodontomys megalotis megalotis= (Baird)

Western harvest mouse

_Reithrodon megalotis_ Baird, Mamm. N. Amer., p. 451, 1857.

_Reithrodontomys megalotis nigrescens_ Howell, N. Amer. Fauna,
36:32, June 5, 1914 (type from Payette, Idaho).

_Reithrodontomys megalotis megalotis_ Bailey, N. Amer. Fauna,
55:189, August 29, 1936.

_Type._--Obtained between Janos, Chihuahua, and San Luis Springs,
New Mexico, by C. B. R. Kennerly, in 1855; type in United States
National Museum.

_Measurements._--Five males and 6 females, showing moderate wear on
the third upper molars, from Walla Walla County, average,
respectively: total length 141, 137.5; length of tail 71.8, 68.1;
hind foot 17.2, 16.7; weight (males only) 10.5 grams. A female, 136
mm. long, from Grant County, weighed 9.5 grams. Over the range of
_megalotis_ in the United States, males average consistently larger
than females in length of the hind foot and consistently less in
length of head and body.

_Distribution._--The Columbian Plateau, the Upper Sonoran
Life-zone area west of the Columbia River and south of the
Wenatchee Mountains in Kittitas, Yakima, and Benton counties, the
north side of the Columbia River in Klickitat County, and Okanogan
County east of the Okanogan River. Marginal localities are:
Timentwa (W. W. D.) on the north, Maryhill (M. V. Z.) on the west,
Wallula (M. V. Z.) on the south, and Colfax (Taylor and Shaw,
1929: 21) on the east.

_Remarks._--Harvest mice from the states of Washington, Oregon, Idaho, Utah, Nevada, California, Arizona, and New Mexico were examined to ascertain the validity of the name _Reithrodontomys megalotis nigrescens_ Howell (type from Payette County, Idaho). No cranial characters or measurements could be found to separate _nigrescens_ from _megalotis_. Specimens from Washington, Oregon, and west-central Idaho, within the range ascribed to _nigrescens_, averaged slightly darker in color with a more distinct, blackish dorsal line than specimens from New Mexico. This difference is slight, and specimens from any one locality vary greatly in color. Some Washington specimens are as pale as the palest material from New Mexico, and some of the darkest _nigrescens_ can be matched by specimens of _megalotis_ from Arizona and New Mexico. This slight color variant is not worthy of recognition as a distinct subspecies, and I agree with Howell (1939: 390) that _nigrescens_ is a synonym of _megalotis_.

_Description._--The western harvest mouse is about the size and shape of the common house mouse. The length of the tail is approximately equal to the length of the head and body. The tail is slim and lightly haired. The upper parts are brownish buff lightly washed with blackish. A faint but distinct dark dorsal stripe is usually present. The underparts are white. From _Mus_ and _Peromyscus_, _Reithrodontomys_ can be distinguished by the grooves on the anterior face of the upper incisors and the long brown hairs at the bases of the ears.

This genus reaches the extreme northern limit of its distribution in the state of Washington, where it ranges to the Canadian border. A single subspecies occurs in Washington. The harvest mouse is a resident of the Upper Sonoran Life-zone and it is most abundant in dense growths of grass, weeds, and other vegetation. Along the Yakima River, near Ellensburg, it was abundant in thick, river-side jungle. Near Yakima many specimens were taken in a marsh of cattails and tules. In the Grand Coulee they live in thick grass. Near Moses Lake several were found in their nests in a thick growth of tumbleweed. Harvest mice occur also, although never in great numbers, in relatively open areas. At the Potholes near Moses Lake, Grant County, a few were caught on sand dunes among scattered bushes of sage. They were taken on sagebrush flats in several localities. Gray (1943: 191) estimates their numbers in the sagebrush area of the Yakima Valley at 5 per acre.

Where harvest mice live in dense vegetation they make small runways and food piles similar to those of _Microtus_ but in more open areas they leave no perceptible signs. Near Yakima the nest of a harvest mouse was found among the roots of an overturned apple tree. This nest was an irregular ball composed of fine grasses and shredded bark closed above, with a side entrance and a central cavity three inches in diameter. Near Moses Lake three nests of harvest mice were discovered on the ground under cover of a dense growth of tumbleweed, and six live harvest mice were captured in the same area. These nests were cuplike, open above, and were composed of dry grasses, bits of weeds, and newspaper. The smoothly rounded inner cups measured about three inches in diameter.

Embryos were found in harvest mice in Washington from March to April and numbered 3 to 6.

=Peromyscus maniculatus= (Wagner)

Deer mouse

_Description._--The deer mouse is slightly larger than the house mouse, the head and body measuring from 3-1/2 to 4 inches. The length of the tail varies considerably in the several races, ranging from approximately 2-1/2 inches in _gambelii_ to 4 inches or more in some individuals of _oreas_. The eyes are large and protrude slightly. The ears are large, erect and naked. The tail is sparsely furred with short, posteriorly directed hairs. The color of the upper parts varies from yellowish buff in _gambelii_ to reddish brown in _oreas_ and dusky in _austerus_. Young deer mice are gray or bluish gray above. Underparts and feet are white. The tail is bicolored, being dusky above and white below.

In Washington _Peromyscus_ may be separated from other naked-eared mice by ungrooved teeth and slightly tapering, bicolor tail. Nearly every part of North America is inhabited by one or more kinds of _Peromyscus_. The single species, _maniculatus_, which occurs in Washington, ranges from the Atlantic to the Pacific and from the Arctic to tropical Mexico. Osgood (1909: 17) remarks: "... it is probable that a line, or several lines, could be drawn from Labrador to Alaska and thence to southern Mexico throughout which not a single square mile is not inhabited by some form of this species."