Part 31

Female: Five adults and subadults have corresponding measurements as follows: 247 (241-257); 69 (66-73); 30.0 (28.0-32.0).

Color.--As described in Mustela erminea streatori except that: occasionally white in winter; upper parts about tone 2 of Dark Chocolate of Oberthür and Dauthenay; least width of color of underparts averaging, in 7 adult males, 6 (0-15) per cent of greatest width of color of upper parts. Black tip of tail in same series averaging 37 (26-46) mm. which is 46 (32-54) per cent of length of tail-vertebrae.

Skull.--Male (based on 13 adults): See measurements and plates 5-7. As described in Mustela erminea richardsonii except that: Weight, 1.2 (1.0-1.3) grams; basilar length, 34.0 (32.5-35.6); length of tooth-rows more or less (usually less) than length of tympanic bulla.

Female (based on 5 adults): See measurements and plates 11-13. As described in Mustela erminea richardsonii except that: Weight 0.9 (0.77-1.06) grams; basilar length, 31.5 (30.9-31.8) grams; length of tooth-rows more or less than (approximately same as) length of tympanic bulla; breadth of rostrum more than 30 per cent of basilar length.

The sexual dimorphism in the skull is slight, the skull of the male being only a third heavier than that of the female. In fallenda of the adjacent mainland to the east the male is three-fourths heavier than the female. In comparison with fallenda, males are smaller, averaging less in every cranial and dental measurement taken and by weight are a fifth lighter; sagittal crest absent rather than present; tympanic bullae flush with squamosal rather than projecting below floor of braincase; in relation to basilar length, tympanic bullae smaller, braincase deeper and broader, skull wider interorbitally and across zygomata. Females are larger than in fallenda, and with one exception average larger in every cranial and dental measurement taken, being 6 per cent heavier. The one exception mentioned is the lesser actual length of the tympanic bulla in anguinae, in which the length of the tooth-rows is about the same as, rather than less than, the length of the tympanic bulla. The postorbital breadth is greater than in fallenda and the anterior edges of the tympanic bullae are flush with the squamosals rather than projecting below the floor of braincase. In relation to the skull as a whole the preorbital and interorbital parts are larger.

In comparison with streatori, skulls of males are of about the same size, anguinae being only 9 per cent heavier. The length of the tooth-rows is ordinarily less than, rather than about equal to, the length of the tympanic bulla; sagittal crest wanting rather than present since in anguinae the temporal muscles meet usually only at the posterior end of the braincase instead of all along the midline on its top; tympanic bullae narrower and more nearly flush with squamosal (less protruded from braincase). Relative to the basilar length, the zygomatic breadth is more, the tympanic bullae are narrower, and the braincase is deeper at the anterior end of the basioccipital. The female is 41 per cent heavier than streatori, there being no overlap in most cranial and dental measurements. M1, however, is approximately the same size in each subspecies. The tooth-rows and tympanic bulla are of almost equal length whereas in streatori the length of the tooth-rows is less than that of the bulla.

Differences from olympica, in males, are: M1 shorter; all other measurements of teeth and parts of skull averaging larger; skull 20 per cent heavier; tooth-rows averaging shorter than tympanic bulla rather than about the same; relative to basilar length, braincase deeper at anterior end of basioccipital and tooth-rows shorter. The skull of the female is 64 per cent heavier, larger in every measurement taken without overlap; temporal ridges meeting, rather than separated, at lambdoidal crest; length of tooth-rows about equal to, rather than shorter than, tympanic bulla; in relation to basilar length, skull deeper, orbitonasal length more, mastoid and zygomatic breadths more, and tympanic bullae shorter.

Remarks.--References in the literature to this insular race mostly were under the name streatori until 1932 when in the course of the present study the name anguinae was proposed. A few specimens have been taken by nearly every student of small mammals who has collected on Vancouver Island. Arthur Peake and Herbert Laing have probably collected more specimens than any other two zoölogists.

M. c. anguinae is noteworthy for the slight secondary sexual variation in size; the disparity between the two sexes is less than in any other American subspecies of erminea. By linear measurement the body of the female is only 7 per cent shorter than in the male (178 versus 191 mm.). Linear measurements and weights of the skulls of the two sexes are further indicative of this approximation in size. By weight the skull of the female is only a fourth lighter than that of the male, or, stated in another way, the male's skull is only a third heavier (1.2 versus 0.9 grams).

No geographic variation has been detected between lots of specimens from different parts of Vancouver Island. The one specimen available from Salt Spring Island presents no obvious differences from selected individuals from Vancouver Island.

The winter pelage is more often brown than white. Of 17 specimens seen in winter pelage or in transition pelage, only 6 are white. These 6 are from Comox, Stamp River, Hilliers, Jeune Landing and Port Alice. Of the 34 specimens in brown pelage, 7 have the dark color of the upper parts meeting on the abdomen. Six of the 34 have brown color on the pectoral region. In two, this is a separate patch but in the other four the dark color is a continuation of the upper parts and extends in front of each foreleg over part of the pectoral region, but the two extensions, one from either side, do not meet on the underparts. The color of the lips was recorded in 22 individuals: one had both the upper and lower-lips white; 7 had the upper lips brown and the lower lips white; in 14 both the upper and lower-lips were brown.

Specimens examined.--Total number, 40, listed by localities from north to south as follows. Unless otherwise indicated, specimens are in the National Museum of Canada.

=British Columbia.= Vancouver Island: Cape Scott, 4; Shushartie, 1; Quatsino, 1; Jeune Landing, 1; Port Alice, 5; Marble Creek, Quatsino Sound, 1; Port Hardy, 5; Sayward, 2; Bear Lake, 4; Bear River, 1; Comox, 4(3); Stamp River, Alberni, 1; Errington, 1; French Creek, 1; Hilliers, 1; Craigs Crossing, 1; Nanaimo, 2; Cowichan Lake, 1; Duncan, 2; Salt Spring Island, 1.

=Mustela erminea fallenda= Hall

Ermine

Plates 5, 6, 7, 11, 12 and 13

Mustela erminea fallenda Hall, Journ. Mamm., 26:79, February 27, 1945; Hall, Journ. Mamm., 26:181, July 19, 1945.

Putorius streatori Merriam, N. Amer. Fauna, 11:13, June 30, 1896 (part-Sumas).

Type.--Male, adult, skull and skin; no. 7096, Nat. Mus. Canada; Huntingdon, British Columbia; May 21, 1927; obtained by C. H. Young, original no. 317.

The brown summer skin is well made. The skull (plates 5-7) is complete. Right p2 has the crown broken away; otherwise the teeth all are present and entire.

Range.--On mainland in immediate vicinity of coast from probably opposite Texada Island, British Columbia, south to Lake Whatcom, Washington, and east to Mount Baker Range on International boundary. See figures 25, 27 on pages 95, 149.

Characters for ready recognition.--Differs from M. e. haidarum, in both sexes, in light-colored underparts less than half the width of dark-colored upper parts, proximal two-thirds of under surface of tail colored like upper parts instead of underparts, interorbital breadth less than distance between glenoid fossa and posterior margin of external auditory meatus; from M. e. richardsonii in both sexes, by upper lips brown rather than white, in males hind foot less than 41 and basilar length less than 38.3, in females hind foot less than 29, basilar length less than 31.4 and breadth of rostrum more, instead of less, than 30 per cent of basilar length; from M. e. invicta, in both sexes, by upper lips brown (not white); in males by skull averaging shorter (basilar length 35.7 versus 37.0); in females by breadth of rostrum more, instead of less, than 30 per cent of basilar length; from M. e. anguinae, in both sexes, by anterior margin of tympanic bulla projecting from floor of braincase rather than flush with squamosal (the difference is slight in females), in males by sagittal crest present, in females by total length less than 238 and tooth-rows longer than, instead of about same length as, tympanic bulla; from M. e. streatori, in both sexes, by black tip of tail more than half of length of tail-vertebrae, in males hind foot more than 33.7, tympanic bulla longer than, instead of about same length as, upper tooth-rows; weight of skull more than 1-1/4 grams, in females weight of skull more than 0.7 grams, length of lateral side of P4, 4 mm. or more; from M. e. olympica, in males, length of hind foot more than 33, black tip of tail more than 36.5 mm., weight of skull more than 1.2 grams, basilar length more than 33.5, in females length of hind foot more than 25.5, weight of skull more than 0.66 grams, basilar length more than 28.4; from M. e. gulosa, in both sexes, by anterior margin of tympanic bulla projecting below floor of braincase rather than flush with squamosal (the difference is slight in females), in males hind foot more than 33.5, weight of skull more than 1-1/4 grams, basilar length more than 33.9, in females by total length more than 222, hind foot longer than 26, weight of skull more than 0.7 grams, basilar length more than 29.

Description.--Size.--Male: Seven adult topotypes yield average and extreme measurements as follows: Total length, 278 (249-305); length of tail, 77 (69-81); length of hind foot, 36.5 (34-40). A male topotype of unknown age weighed 113 grams.

Female: Two adult topotypes, with actual measurements in parentheses, average as follows: Total length, 232 (228-236); length of tail, 60 (57-62); length of hind foot, 27 (27-27). An adult from Morovitz Guard Station, Wash., weighed 54 grams.

Color.--Winter pelage rarely white, brown pelage indistinguishable from summer pelage except for slightly more smoky tinge in winter in specimens from some localities; otherwise as described in Mustela erminea streatori except that least width of color of underparts averaging, in seven adult topotypes, 18 (0-37) per cent of greatest width of color of upper parts. Black tip of tail averaging, in same series, 45 (38-52) mm. which is 58 (53-65) per cent of length of tail-vertebrae.

In comparison with richardsonii and invicta, fallenda differs in darker color of upper parts and their extension at the expense of the light-colored underparts which are narrower by a half. In correlation with this restriction in area of the light-colored underparts, the upper lips are brown instead of white. In comparison with anguinae, olympica and streatori, the longer black tip on the tail is the principal difference in color. From gulosa, fallenda differs in slightly darker color of upper parts and in narrow underparts, the width of the same being only about a fifth instead of a third of the width of the dark-colored upper parts.

Skull.--Male (based on 7 adults): See measurements and plates 5-7. As described in Mustela erminea richardsonii except that: Weight, 1.5 (1.3-1.7) grams; basilar length, 35.7 (34.3-38.2).

Female (based on 6 ads.): See measurements and plates 11-13. As described in Mustela erminea richardsonii except that: Weight, 0.85 (0.73-1.0) grams; basilar length, 30.6 (29.4-31.7); breadth of rostrum more than 30 per cent of basilar length.