Part 25

Skull.--Male (based on adults from Aitkin): See measurements and plates 2-4. As described in Mustela erminea richardsonii except that: Weight of 2 adults from Aitkin, 2.2, 2.3 grams (9 subadults from T. 61 N, R. 26 W, average 1.95 grams); basilar length, 39.7 (38.5-40.7); length of tooth-rows rarely more (usually less) than length of tympanic bulla.

Female (based on adults from Minnesota as listed in table of cranial measurements, which see): See plates 9-11. As described in Mustela erminea richardsonii except that: Weight, of a subadult from T. 61 N, R. 26 W, 0.91 grams; basilar length, 32.8 (31.8-33.6); breadth of rostrum rarely equal to as much as 30 per cent of basilar length.

From richardsonii, topotypes of bangsi differ in that cranial measurements in males are approximately 7 (5-9) per cent less, linear measurements of teeth are 10 (9-11) per cent less and the skull is a fifth lighter. In relation to basilar length the tympanic bullae of bangsi are longer. Skulls of females are individually indistinguishable, those of bangsi averaging approximately 1 per cent less in linear measurements. Comparison with the smaller cicognanii is made in the account of that subspecies.

Remarks.--Before the subspecific name bangsi was proposed, individuals of this subspecies ordinarily were recorded in the literature as Mustela cicognanii. The best single lot of material is in the zoölogical collection of the University of Wisconsin. The late naturalist Albert Lano preserved a large share of the material from Minnesota. The large series from Elk River of that same state was mostly collected by Bernard Bailey although his Aunt, Anna (Bailey) Mills, and her brother the late Vernon Bailey, at an earlier time saved some specimens from Elk River. The name bangsi was proposed in recognition of the superior work done on American weasels by the late Outram Bangs.

From the range of M. e. invicta in the Rocky Mountains, that of bangsi is separated by the Great Plains from a large part of which region the species is unknown. M. e. bangsi differs from invicta in greater degree of sexual dimorphism in size, and in each sex by larger size, narrower light-colored underparts, and deeper braincase as measured at the anterior margin of the basioccipital. In bangsi the braincase is deeper relative to the length of the skull as well as, of course, actually deeper.

Of the two subspecies whose ranges do meet that of bangsi, it more closely resembles richardsonii than cicognanii. From richardsonii, especially from southeastern populations of the same in which the skull is of the same size as in bangsi, the latter differs in longer hind feet. This is an average difference and by one interpretation the animals here referred to bangsi might be lumped with some of the populations from the southeastern part of the range of richardsonii and the whole lot treated as intergrades between richardsonii and cicognanii. Nevertheless, the animals here referred to bangsi are not geographically intermediate between richardsonii and cicognanii and this consideration had much to do with the decision to recognize as a separate subspecies the animals here named bangsi.

Within the range of the subspecies there is some geographic variation; the hind feet of animals from Iowa average slightly shorter than those of animals from Minnesota and Wisconsin but are nowhere nearly so short as in cicognanii at the same latitude in the eastern United States.

It is noteworthy that the few specimens seen from Isle Royal have the long hind feet of bangsi and not the short hind feet of cicognanii which occurs all along the northern mainland.

Because an oft cited record of occurrence even though erroneous, has a way of being repeated in later works, attention is here called to the alleged occurrence of this ermine in northwestern Ohio at New Bremen. Henninger (1921:239) published the original account of the supposed occurrence but as I pointed out in 1937 (p. 304), the specimen concerned proved upon examination to be a female of Mustela frenata noveboracensis. Henninger was misled probably by the short tail; the end of the tail had been lost and healed over before the animal's death. The present study has revealed that M. erminea everywhere east of the Cascade Mountains assumes a white winter coat. Had this been known when Henninger obtained his specimen he probably would not have wrongly identified the animal from New Bremen which was in the brown, winter pelage.

Specimens examined.--Total number, 222, arranged alphabetically by provinces and states and, arranged from north to south, by counties in each state. Unless otherwise indicated, specimens are in the University of Wisconsin Museum of Zoölogy.

=Iowa.= Dickinson County: W side Lake Okobogie, 1. Winnebago County: Lake Mills, 7. Worth County: Northwood, 1. Clay County: "Dewey's Pasture, near Ruthven," 1.

=Manitoba.= Aweme, 4; Red River Settlement, 1.

=Michigan.= Isle Royal: Tobin Harbor, 1; Bell Isle, 1; Washington Harbor, 3. Ontonagon County: Ontonagon, 2 (1, 1); T. 51N, R. 43W, S. 17, Porcupine Mts., 1. Gogebic County: Little Girls Point, 5; Ironwood, 1. Iron County: no locality more definite than county, 1. Luce County: Tahquamenon River Falls, 1. Chippewa County: Sault Ste. Marie, 2. Emmet County: Wilderness State Park, 2. Cheboygan County: Univ. Mich. Biol. Station, 1. Washtenaw County: Ann Arbor, 1.

=Minnesota.= Kittson County: no locality more definite than county, 1. Roseau County: Deer Township, 1; Falun Township, 2. Marshall County?: Moose River, 5; Warren, definitely in Marshall County, 1. Cook County: Grand Marais, 3 (2, 1). St. Louis County: 2 mi E Babbitt, 14; Burntside [= Burnside] Lake, 1. Itasca County: T. 61N, R. 26W, 23. Clay County: Moorhead, 3. Aitkin County: Aitkin, 13 (11, 1, 1). Otter Tail County: Arthur, 3; Ten Mile Lake, 1; Parkers Prairie, 2. Chisago County: North Branch, 1. Sherburne County: Elk River, 42 (16, 5, 20, 1). Hennepin County: Lake Minnetonka, 1; Minneapolis, 1; Fort Snelling, 5 (4, 1).

=North Dakota.= Pembina County: Walhalla, 1. Nelson County: Stump Lake, 1. Eddy County: Brantford, 2.

=Wisconsin.= Douglas County: T. 44N, R. 13W, 1; Gordon, 1. Bayfield County: Brinks Camp, Washburn, 1; "near Cable," 1. Ashland County: Bear Lake, 2. Iron County: Fisher Lake, 4; Mercer, 5. Vilas County: Mamie Lake, 16; Ox Bow Lake, 1. Oneida County: Tomahawk Lake, 1. Langlade County: T. 34N, R. 11E, 3. Rush County: Ladysmith, 1. Dunn County: Colfax, 2. Door County: Mink River, Ellison Bay, 1. Dodge County: Fox Lake, 1; Beaver Dam, 12.

=Mustela erminea invicta= Hall

Ermine

Plates 2, 3, 4, 9, 10, 11 and 41

Mustela erminea invicta Hall, Journ. Mamm., 26:75, February 27, 1945; Hall, Journ. Mamm., 26:180, July 19, 1945.

Putorius cicognanii, Preble, N. Amer. Fauna, 27:230, October 26, 1908.

Type.--Male, subadult, skull and skin; no. 101122, Mus. Vert. Zoöl.; Benewah, Benewah County, Idaho; October 24, 1926; obtained by William T. Shaw.

The skull has a hole in the right squamosal bone on the floor of the braincase, and lacks the hamular process of the left pterygoid. The postmolar part of the right lower jaw is missing. The teeth all are present and entire. The skin is in white, winter pelage, well made, and in a good state of preservation.

Range.--Central Rocky Mountain region from Jasper Park south over Alberta, southeastern British Columbia, Washington east of the Cascades, and north and central Idaho and northwestern Montana. See figure 25 on page 95.

Characters for ready recognition.--Differs from M. e. richardsonii, in males, by skull lighter than 1.9 grams, mastoid breadth less than 19.9, depth of skull at anterior margin of basioccipital less than 12.4, in females by corresponding measurement of depth less than 10.1, and weight of skull less than one gram; from M. e. fallenda, in both sexes, by upper lips white (not brown), in males by skull averaging longer (37.0 versus 35.7), in females by breadth of rostrum less, instead of more, than 30 per cent of basilar length; from M. e. streatori, gulosa, and muricus by hind foot more than 36 and basilar length more than 35 in males and by hind foot more than 29.5 and basilar length more than 30.5 in females; further distinguished from streatori by white (not brown) upper lips and from gulosa by black tip of tail more than half length of tail-vertebrae.

Description.--Size.--Male: Ten adults and subadults from central Idaho County yield average and extreme measurements as follows: Total length, 291 (272-328); length of tail, 86 (75-100); length of hind foot, 39.9 (38-44).

Female: Five adults and subadults from the same locality yield average and extreme measurements as follows: Total length, 255 (245-270); length of tail, 71 (68-76); length of hind foot, 32.3 (32-33).

Color.--As described in Mustela erminea richardsonii except that underparts in summer Marguerite Yellow or more whitish; least width of color of underparts averaging, in four females from Idaho and Montana, 38 (33-43) per cent of greatest width of color of upper parts. Black tip of tail in same specimens 38 (31-42) mm. which is 57 (52-65) per cent of length of tail-vertebrae.