Part 19

Of the 21 specimens in winter pelage, 17 are white and four are brown. The brown winter coat is distinctly paler, with more of a smoky tinge, than the brown summer pelage. The light-colored underparts are narrower than in the subspecies immediately to the east but are wider than in the coastal forms to the west. The dark color of the upper parts extends onto the chest in front of the forelegs, as in the coastal forms, in only one of the 13 specimens in summer pelage and in it on one side only. The black tip of the tail is short as in the coastal forms. One specimen is in transitional pelage. It has acquired approximately half of the white winter pelage and was taken on October 12, 1897, at Keechelus Lake.

_Specimens examined._--Total number, 38, arranged by counties from north to south. Unless otherwise indicated, specimens are in the U. S. National Museum.

=Washington.= _King County_: 2 mi. E Skykomish, 2[51]. _Kittitas County_: Keechelus Lake, 3 (1[1]); Martin, 1[1]; Easton, 3. _Pierce County_: James Lake, 4370 ft., Mt. Rainier, 1; Glacier Basin, 5935 ft., Mt. Rainier, 1; Meslers Ranch, 2000 ft., 1 mi. W Rainier Park, 1. _Lewis County_: Mt. Rainier Nat'l Park, 5 (1 each from: Paradise Park, 5400 ft.; Reflection Lakes, 4900 ft.; Ohanapecosh [Hot] Springs, 2000 ft.; Tahoma Creek, 1[72]; Bear Prairie); also in Mt. Rainier Nat'l Park, Longmire, 3 (1[72], 1[94]). _Skamania County_: Mt. St. Helens, 6000 ft., 1. _Klickitat County_: Trout Lake, 18.

=Mustela erminea muricus= (Bangs)

Ermine

Plates 7, 8, 12, 13, 14 and 41

_Putorius (Arctogale) muricus_ Bangs, Proc. New England Zoöl. Club, 1:71, July 31, 1899.

_Putorius streatori leptus_ Merriam, Proc. Biol. Soc. Washington, 16:76, May 29, 1903. Type from Silverton, San Juan County, Colorado.

_Putorius muricus_, Stephens, California Mammals, p. 248, 1906.

_Putorius cicognani_, Taylor, Univ. California Publ. Zoöl., 7:298, June 24, 1911.

_Mustela streatori leptus_, Miller, U. S. Nat. Mus. Bull., 79:96, December 31, 1912; Bailey, N. Amer. Fauna, 35:48, September 5, 1913; Dixon, Journ. Mamm., 12:72, February 12, 1931; Whitlow and Hall, Univ. California Publ. Zoöl., 40:246, September 30, 1933.

_Mustela muricus_, Miller, U. S. Nat. Mus. Bull., 79:96, December 31, 1912; Kellogg, Univ. California Publ. Zoöl., 12:358, January 27, 1916.

_Mustela cicognanii lepta_, Dice, Journ. Mamm., 1:12, November 28, 1919; Hall, Mamm. Nevada, p. 184, July 1, 1946.

_Mustela rixosa_, Seton, Journ. Mamm., 14:70, February 14, 1933.

_Mustela cicognanii leptus_, Miller, Journ. Mamm., 14:368, November 13, 1933; Bailey, N. Amer. Fauna, 55:293, August 29, 1936.

_Mustela erminea murica_, Hall, Journ. Mamm., 26:84, February 27, 1945; Hall, Journ. Mamm., 26:181, July 19, 1945.

_Type._--Male, young, skull and skin; no. 9146, collection of E. A. and O. Bangs in Mus. Comp. Zoöl.; Echo, 7500 ft., El Dorado County, California; July 15, 1897; obtained by W. W. Price and E. M. Nutting.

The skull has a fracture along the sagittal suture and fractures on the left side of the braincase but these have been glued, and no part of the skull is missing except in the region of the right P4 which part has been shot away. On the left side m2 never developed. Excepting this tooth and the right P4, all the teeth are present and entire. The skin is well made but has the soles of the hind feet turned up.

_Range._--Near 5300 feet (Denver) to 11000 feet (Santa Fe Baldy); typically boreal but taken in Upper Sonoran Life-zone in winter at Denver; from central and southwestern Montana, southern Idaho, and Blue Mountains of southeastern Washington southward east of the Cascade Divide through the Salmon River Mountains and Sierra Nevada at least into Fresno County of California, in the Great Basin to central Nevada, in the Rocky Mountains into northern New Mexico; eastward to the Black Hills. See figure 25 on page 95.

_Characters for ready recognition._--Differs from _M. e. invicta_ by hind foot less than 36 and basilar length less than 35 in males and by hind foot less than 29.5 and basilar length less than 30.5 in females; from _M. e. gulosa_, in both sexes, by upper parts lighter, tone 2 of Chocolate or lighter (see description of color), least width of light-colored underparts averaging about two-thirds instead of one-third of greatest width of dark-colored upper parts, in males, on the average, tail less than 65, weight of skull less than 0.90 grams, basilar length less than 30.8 grams; from _M. e. streatori_, in both sexes, by upper lips white (not brown), light color of underparts extending down hind leg below knee, depth of skull at posterior border of upper molars less than 7.7 in females and ordinarily less than 9.6 in males, tail less than 62 in males and less than 49 in females.

_Description._--_Size._--Male: An adult from Black Butte, California, measures: Total length, 227; length of tail, 55; length of hind foot, 27. Corresponding measurements of another from Wheeler Peak, Nevada, are: 220, 56, 26. Two subadults from Colorado, one from Crested Butte and another from Coventry, measure, respectively, as follows: 238, 227; 66, 60; 30, 30. An adult from Wheeler Peak, Nevada, weighs 57.7 grams and another from 2 mi. W Black Butte, Calif., 54.5 grams.

Female: Two adults from Teton County, Wyoming, measure: Total length, 205, 200; length of tail 52,--; length of hind foot, 23, 23.7. A subadult from 9-1/2 mi. E Pocatello, Idaho, measures: 197, 50, 25. An adult from Wheeler Peak, Nevada, has corresponding measurements of 190, 42, 23, and weighs 33.8 grams.

_Color._--As described in _Mustela erminea richardsonii_ except that upper parts tone 2 or lighter of Chocolate of plate 343 of Oberthür and Dauthenay; underparts white, Pale Buff or with faint wash of Sulphur Yellow; least width of color of underparts in male from Black Butte and one from Wheeler Peak, amounting to 65 and 59 per cent of greatest width of color of upper parts. Black tip of tail, respectively, 28 and 33 mm., which amounts to 51 and 59 per cent of length of tail-vertebrae. In two adult females, one from Teton County, Wyoming, and one from Wheeler Peak, Nevada, the least width of the underparts amounts to 55 and 60 per cent of the greatest width of color of upper parts. Black tip of tail, respectively, 23 and 19 mm., which amounts to 44 and 45 per cent of length of tail-vertebrae.

From the other subspecies of small-sized weasels of more northwestern occurrence, namely _anguinae_, _fallenda_, _olympica_, _streatori_ and _gulosa_, _muricus_ differs in lighter color of upper parts, wider light-colored underparts and relatively longer black tip of tail.

_Skull._--Male (illustrated by 5 adults in table of measurements, which see): See plate 7. As described in _Mustela erminea richardsonii_ except that: Weight, 0.78 (Wheeler Peak) and 0.85 (Black Butte) grams; basilar length, 30.6 (29.8-31.2); length of tooth-rows more or less than (approximately equal to) length of tympanic bulla.

Female (illustrated by 6 adults in table of measurements, which see): See plates 12-14. As described in _Mustela erminea richardsonii_ except that: Weight, 0.60 (0.575-0.645); basilar length, 28.0 (27.3-29.4); breadth of rostrum approximately 30 per cent of basilar length.

In comparison with _streatori_, males average smaller in every measurement taken with no overlap in most dimensions; 25 per cent lighter; anterior margin of tympanic bulla more nearly flush with squamosal, that is to say less protruded from braincase; in relation to other dimensions of skull, braincase shallower anteriorly (at plane of last molars) and deeper posteriorly (at anterior end of basioccipital). Females average smaller in every measurement taken except mastoid and zygomatic breadths which are actually more; 6 per cent lighter; in relation to other parts of skull, preorbital and interorbital parts slightly smaller; in relation to length of skull, braincase shallower. Comparison with _invicta_ and _gulosa_ is made in the accounts of those subspecies.

_Remarks._--The smallest males of the entire species are of this subspecies and the females of it are barely larger than those of _olympica_ and _gulosa_ and hence are among the three smallest. The material now available consists only of one or a few specimens from each of several widely separated localities. If as many specimens per unit area were available as there are of the species _M. erminea_ from southern British Columbia, geographic variation warranting the division of _muricus_ into more than one subspecies might be revealed. Evidence pointing in this direction is comprised in the pale color and small size of the pair of adults from Wheeler Peak on the eastern border of Nevada; the suggestion is that there is a distinct pale race of small individuals in the isolated spots of boreal life-zone in the mountains of the desert. The color and size of the specimens from the Toyabe Mountains, and that from the Pine Forest Mountains, both places also in Nevada, nevertheless, lend no support to this suggestion. Comparison of specimens from the Rocky Mountains of Colorado with those from the Sierra Nevada of California gives no basis for recognizing more than one subspecies. Therefore, _Putorius streatori leptus_ Merriam with type locality at Silverton, San Juan County, Colorado, falls as a synonym of the earlier named _Putorius (Arctogale) muricus_ Bangs with type locality at Echo, El Dorado County, California. Furthermore, specimens from northern New Mexico, the southernmost known area of occurrence for the subspecies (and for the species), are as large as specimens from far north in the range of the subspecies, say, in northwestern Wyoming; there is therefore no evidence of progressive decrease in size to the southward as in advance of study I supposed existed in _muricus_. This erroneous supposition was held because I knew that there was a decrease in size to the southward in the species as a whole and also in each of the subspecies _richardsonii_ and _invicta_ directly to the north of _muricus_.

Intergradation with _invicta_ is shown by specimens from southwestern Montana. Where the margins of the geographic ranges of _invicta_ and _muricus_ approach one another elsewhere, low-lying territory, zonally unsuited to the existence of the species, occurs along the Snake and Columbia rivers, and precludes any chance of intergradation except around the head of the Snake River Plains. Two specimens, here referred to _muricus_, from Siskiyou County, California, in both color and cranial characters, are intergrades with _streatori_ and might be referred with almost equal propriety to _streatori_.

_Specimens examined._--Total number, 52, arranged alphabetically by states, then by counties from north to south within each state. Unless otherwise indicated, specimens are in the Museum of Vertebrate Zoölogy, University of California at Berkeley.

=California.= _Siskiyou County_: head of Rush Creek, 6400 ft., 1; Castle Lake, 5434 ft., 1. _Tehama County_: 2 mi. W Black Butte, 6800 ft., 1. _Placer County_: ridge W of Tahoe Pines, Lake Tahoe, 1; Blackwood Creek, 6250 ft., near Tahoe Pines, 1. _El Dorado County_: Fallen Leaf Lake, 6500 ft., 1[33]; Echo, 1[75]. _Tuolumne County_: Ten Lakes, 9200 ft., Yosemite Park, 1. _Mariposa County_: Vogelsang Lake, 10350 ft., Yosemite Park, 1. _Mono County_: Mammoth, 1[59].

=Colorado.= _Rio Blanco County_: Marvine, 1. _Boulder County_: Camp Albion, 10600 ft., 1[60]; Boulder, 1[91]. _Denver County_: Denver, 1[57]. _Park County_: Jefferson, 1[57]. _Gunnison County_: near Placita in Gunnison County, 1[26]; Crested Butte, 9000 ft., 3 (1[91], 2[19]). _El Paso County_: Turkey Creek, SW Colorado Springs, 6000 ft., 1[19]. _Chaffee County_: Arbourville, 1[91]; Hancock, 1. _Montrose County_: Coventry, 6800 ft., 1[19]. _San Juan County_: Silverton, 1[91]; in San Juan County above timberline, 1[87].

=Idaho.= _Bannock County_: West Fork of Rapid Creek, 9-1/2 mi. E Pocatello, 1.

=Montana.= _Meagher County_: Camas Creek, Big Belt Mts., 4 mi. S Ft. Logan, 1[91]. _Beaverhead County_: Donovan, 1[91]. _County_ in question: Yellowstone Park, 1[75].

=Nevada.= _Humboldt County_: Alder Creek, 6000 ft., Pine Forest Mts., 1. _Ormsby County_: 1/2 mi. S Marlette Lake, 8150 ft., 1. _Nye County_: South Twin River, Toyabe Mts., 1[91]. _White Pine County_: Baker Creek (8500 ft., 8675 ft., 11100 ft.), 3.

=New Mexico.= _Taos County_: Twining, 10700 ft., 1[91]. _Sandoval County_: 9 mi. E Cuba, 9000 ft., 1. _Santa Fe County_: Saddle S of Santa Fe Baldy, 11000 ft., Santa Fe Range, 1[1].

=Oregon.= _Wasco County_: Mill Creek, 20 mi. W Warmsprings, 1[91]. _Klamath County_: Fort Klamath, 1[91].

=South Dakota.= _Pennington County_: 4 mi. SE Hill City, 5300 ft, 2[76]; Pfander's Ranch, 3 mi. SSE Hill City, 5300 ft., 1[76]; Palmer Gulch, 3 mi. SE Hill City, 5300 ft., 1[76]; Spring Creek, 2 mi. W Oreville, 5500 ft., 1[76]. _Custer County_: 1/2 mi. E Sylvan Lake, 6250 ft., 1[76].

=Washington.= _Columbia County_: Butte Creek, 1; Stayawhile Spring, 5150 ft., 1:

=Wyoming.= _Crook County_: 5 mi. NW Sundance, 5900 ft., 1[93]. _Teton County_: Whetstone Creek, 2[76]; 1/4 mi. E Moran, 6700 ft., 1[93]. _Sublette County_: 1/2 mi. NE Pinedale, 7500 ft., 1[93]. _Albany County_: 30 mi. N and 10 mi. E Laramie, 6560 ft, 1[93]; 26 mi. N and 4-1/2 mi. E Laramie, 6960 ft., 1[93]. _Carbon County_: 8 mi. N and 19-1/2 mi. E Savery, 8800 ft., 2[93].

=Mustela erminea? angustidens= (Brown)

Plates 7, 12, 13 and 14

_Putorius cicognanii angustidens_ Brown, Mem. Amer. Mus. Nat. Hist., 9 (pt 4):181, pl. 17, 1908:

_Mustela cicognanii angustidens_, Hay, Iowa Geol. Surv. Bull., 23:32, 1914; Hay, Carnegie Inst. Washington, Pub. no. 322A:252, October 15, 1924; Hay, _ibid_., Pub. no. 390 (vol. 2): 528, 1930; Hall, _ibid_., Pub. no. 473:111, 112, November 20, 1936:

_Type._--Female, adult, skull and lower jaws lacking zygomata, right P2 and incisors, no. 12432, Amer. Mus. Nat. Hist.; from Conard Fissure, four miles west of Willcockson, Newton County, Arkansas; obtained sometime in the period 1903 to 1905 inclusive (see plates 8, 14).

_Range._--Known only from the Pleistocene deposit in Conard Fissure, at the type locality in northern Arkansas.

_Description._--_Skull._--Male (based on nos. 12437, 12441 and 12444): See measurements and plates 7 and 8; weight, unknown; basilar length, 38:1 (36:6-39:2); length of tooth-rows more than length of tympanic bulla; breadth of rostrum measured across lacrimal processes less than a third of basilar length; interorbital breadth ordinarily equal to distance between glenoid fossa and posterior border of external auditory meatus; zygomatic breadth probably averaging approximately the same as distance between last upper molar and jugular foramen.

Female (based on nos. 11766 and 12435): See measurements and plates 8, 12-14; weight, unknown; basilar length, 34:0 (32:5-35:1); length of tooth-rows more than length of tympanic bulla; breadth of rostrum about equal to (more or less than) 30 per cent of basilar length; interorbital breadth less than distance between glenoid fossa and posterior border of external auditory meatus; zygomatic breadth probably less than distance between last upper molar and jugular foramen.

Comparison of the cranial description given above with those of the American races of _erminea_ from the far north will show that many characters are held in common--more than with more southern subspecies of _erminea_.

_Remarks._--The ten specimens studied by the writer fall into two groups of six larger individuals and four smaller. Upon comparing these with each sex of the three species of American Recent weasels, _frenata_, _erminea_ and _rixosa_, it is seen that size, and to some degree shape, rule out of consideration both sexes of _rixosa_ and also males of _frenata_. Thus we are left with females of _frenata_ and males and females of _erminea_. So far as size is concerned, it can be assumed that the larger specimens are females of _frenata_ and that the smaller are males of _erminea_. This assumption has in its favor also, the fact that the postglenoidal length of the skull accords with that in Recent specimens. The difference in this regard in Recent animals is that the postglenoidal length of the skull, expressed as a percentage of the total (condylobasal) length of the skull, amounts to:

in _frenata_ in _erminea_ [M] ordinarily less than 46 [M] ordinarily more than 46 [F] less than 47 [F] more than 48

In the fossils the percentage for the larger skulls is 46; for the smaller skulls it is 48.

It may be that the ten fossil skulls are six female _frenata_ and four male _erminea_ but I think not. In the first place a skull of different shape, seemingly of the _frenata_ stock, is known from the deposit and it is almost certain that two subspecies of the same species would not occur at the same place at the same time. It is possible, of course, that parts of the deposits were laid down at times so far apart that a shift in geographic range of two subspecies had occurred. This one skull, seemingly of the _frenata_ stock, is the type of _Putorius gracilis_ Brown (see p. 404) and was regarded as the only known specimen of _gracilis_. Regardless of the specific identity of this one specimen named _gracilis_, the chances of obtaining otherwise from a deposit, like that in Conard Fissure, six females of frenata and four males of _erminea_ without a male _frenata_ or a female of _erminea_ coming to light are so slight as strongly to incline me to the view that the six larger specimens are males of the same species to which the 4 smaller specimens belong. By either this interpretation, or the one initially considered (of female _frenata_ and male _erminea_), the animals from the fissure are at least subspecifically distinct from any American Recent weasel. Furthermore, by this latter interpretation each sex of this weasel, _angustidens_, is intermediate between the _frenata_ and _erminea_ stocks in the feature of postglenoidal length which feature, at any place where the two Recent species occur together, serves to distinguish one from the other. In the northernmost subspecies of _erminea_ (_arctica_ for example) the postglenoidal length in some males is no longer than in males of _frenata_. Considering general size, _angustidens_ agrees better with _erminea_ than with frenata and this circumstance has influenced me to place _angustidens_ as a subspecies of _erminea_.

Today, _erminea_ is not known to occur nearer Conard Fissure than northern Iowa, more than 400 miles to the northward. In comparison with the race there, _bangsi_, males of _angustidens_ are of approximately the same size but in the shorter distance between the glenoid fossa and anterior margin of the tympanic bulla, and also in the lesser postglenoidal length of the skull, _angustidens_ resembles the northernmost American subspecies of _erminea_. Females of _angustidens_ differ more from any living weasel than the males do. The females are much larger than those of _bangsi_, and among living American races of _erminea_ most closely resemble intergrades between _arctica_ and _richardsonii_ which intergrades are found approximately 1700 miles to the north of Conard Fissure. In females, the preorbital part of the skull in _M. e. arctica_ is broader and in _M. e. richardsonii_ narrower than in _angustidens_. If it seems strange that females of _angustidens_ resemble one subspecies whereas males, in size, resemble another subspecies almost a thousand miles distant, it should be remembered that the degree of sexual dimorphism varies much from one subspecies to another in the Recent animals. An example is furnished by _Mustela erminea fallenda_ and _Mustela erminea invicta_.

The assemblage of mammals from Conard Fissure includes several species of boreal predilections which, like _Mustela erminea_, now occur only much farther north than Arkansas. At one time the edge of the sheet of ice was only about 200 miles north of Arkansas. It may be significant that the cranial characters of the female ermine from the Fissure, and qualitative cranial characters of males from there, are most nearly approximated among Recent weasels by those which live along the southern edge of the frozen tundra.

In view of what has been said, the possibility should be considered that the distinctive cranial features of _angustidens_ may be the result of evolutionary change in time as well as of geographic variation resulting from horizontal placement.

=MUSTELA RIXOSA= (Bangs)

Least Weasel

(Synonymy under subspecies)

_Type._--_Putorius rixosus_ Bangs, Proc. Biol. Soc. Washington, 10:21, February 25, 1896.

_Range._--From Norway and Switzerland eastward through Siberia and all the way across North America, but unknown from Iceland, Greenland and the Arctic islands west of Greenland; in North America, from the Arctic Life-zone south to Central British Columbia, Montana and into parts of the Upper Austral Life-zone as in the eastern half of the continent.

The southern extension of range in the Appalachians (to North Carolina) is not duplicated in the Rocky Mountains of western North America probably because the region there suitable for _rixosa_ south of Central British Columbia and Montana is occupied by the almost equally small _Mustela erminea muricus_ and related subspecies which seem to fill the ecological role that _rixosa_ plays where it occurs. The small size of females of _M. erminea cicognanii_ in New England may similarly account for the absence of _rixosa_ there.

_Characters for ready recognition._--Differs from both _Mustela erminea_ and _Mustela frenata_ by tail a fourth or less of length of head and body and without a black tip (at most a few black hairs at extreme tip in rixosa), and from _M. frenata_ and from _M. erminea_ in regions where it and _rixosa_ occur together, by basilar length of skull less than 32.5 in males and less than 31.0 in females.