Chapter VI: Introduction (5)

Litters of 4, 4, 7, 7, and 8, yielding an average of 6 young per litter have been recorded from the northeastern United States by Hamilton (1933:327). He (_op. cit._:321-325) described animals one day old from New York State as being flesh-colored, having the long neck of the adult and a fine growth of white hair two millimeters in length, on the dorsal surface of the neck, that foreshadows the mane or pompadour that is prominent from the 14th to the 21st day of life. Six animals, when one day old averaged 1.7 grams in weight, which was three per cent of the weight of an adult female and one and one half per cent of the weight of an adult male. At two weeks of age the heavy brown mane stood out in marked contrast to the rest of the scantily, white-furred animal. The eyes opened on the thirty-fifth day of life.

Ventral view of body of a pregnant female to show details of mastology. Note the five pairs of mammae characteristic of weasels, and the uneven arrangement of mammae of the two sides which is also common among weasels.]

For rearing their young, ermines live in burrows. Bishop (1923), in Albany, New York, found a burrow occupied by four young and a pair of adults. The burrow had many galleries and contained a nest constructed of rat fur, fine grass and fragments of leaves. At Woods Lake, Fresno County, California, in early August, Ingles observed (1942) some young and at least one adult at their den which was in a burrow beneath a hollow tree. The ermines used the hollow root and the hollow tree as well as the burrow beneath. Seton (1929 (2):591) quotes S. Eldon Percival, of Barretts Rapids, Ontario, as finding the living quarters of an ermine in unthreshed grain stacked in a barn and says (_op. cit._:590) that John Burroughs dug out a nest, composed of leaves and the fur of mice and moles, two or three handfuls in bulk, from a cavity the size of a hat, arched over with a fine network of tree roots.

Four instances in which the male as well as the female was present at a den containing young are cited by Hamilton (1933:328) and he gives some evidence, although not at all conclusive, that "adults customarily pair, or at least run together, at times other than the breeding season." No other writers remark on this matter. I doubt that adult ermines are associated in pairs for most of the year but such may be the case.

=Mustela erminea arctica= (Merriam)

Ermine

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

_Putorius arcticus_ Merriam, N. Amer. Fauna, 11:15, pl. 2, figs. 1,
1a, and pl. 5, figs. 6, 6a, June 30, 1896.

_Putorius_ (_Gale_) _erminea_, Coues, Fur-bearing animals, p. 109,
1877 (part).

_Putorius richardsonii_, Bangs, Proc. Biol. Soc. Washington, 10:16,
pl. 1, figs. 3, 3a, pl. 2, figs. 3, 3a, and pl. 3, figs. 6, 6a,
February 25, 1896 (part).

_Putorius cicognanii alascensis_, Osgood, N. Amer. Fauna, 19:43,
October 6, 1900.

_Putorius kadiacensis_, Osgood, N. Amer. Fauna, 21:69, September
26, 1901.

_Putorius audax_ Barrett-Hamilton, Ann. and Mag. Nat. Hist.,
13(ser. 7):392, May, 1904, type from Discovery Bay, Ellesmere
Island.

_Putorius alascensis_, Heller, Univ. California Publ. Zoöl., 5:345,
March 5, 1910.

_Mustela arctica arctica_, Miller, U. S. Nat. Mus. Bull., 79:97,
December 31, 1912; Dice, Journ. Mamm., 2:22, February 10, 1921.

_Mustela arctica_, Hall, Univ. California Publ. Zoöl., 30:420,
March 19, 1929.

_Mustela erminea arctica_, Ognev, The mammals of U.S.S.R. and
adjacent countries, 3:31, 1935; Hall, Proc. California Acad. Sci,
23:559, August 22, 1944; Hall, Journ. Mamm., 26:179, July 19,
1945.

_Type._--Male, adult, skull and skin; no. 14062/23010, U. S. Nat.
Mus.; Point Barrow, Alaska; July 16, 1883; obtained by John
Murdock, original no. 1672.

The skull has a fracture, on the dorsal surface, extending from
the anterior nares to the interorbital constriction and another
fracture on the left margin of the nasal bone. The middle of the
left zygomatic arch is broken away. Otherwise the skull is
complete. Right incisor one, above and below, are missing.
Otherwise the teeth are present and entire. The skin is in the
brown summer pelage, well made, in a good state of preservation,
and shows no obvious signs of fading.

_Range._--Arctic regions of Alaska and western Canada from the
Pacific Ocean to Smith Sound; from the northern limit of land
south approximately to a line from Skagway through Ft. Goodhope,
north shore of Great Bear Lake, south shore of Clinton Colden
Lake, north shore of Baker Lake, west end of Wagner Bay to south
end of Committee Bay. See figure 25 on page 95.

_Characters for ready recognition._--Differs from _M. e. polaris_
in darker upper parts (Raw Umber rather than Buckthorn Brown) and
less intensely colored underparts that are Sulphur Yellow,
Colonial Buff or Primrose Yellow rather than Buff Yellow; from _M.
e. semplei_, in males, in that hind foot more than 44 and basilar
length more than 41 and in that females average larger, the skulls
of females being only about 11 per cent heavier; from _M. e.
kadiacensis_ in hind foot more than 33 in females, zygomatic
breadth amounting to more, rather than less, than distance between
last upper molar and jugular foramen irrespective of sex; from _M.
e. richardsonii_, _alascensis_, _salva_ and _initis_, both sexes
so far as known, by proximal two-thirds of under side of tail
colored same as underparts rather than same as upper parts, and by
zygomatic breadth amounting to more, rather than less, than
distance between last upper molar and jugular foramen.

_Description.--Size._--Male: Six adults from Tanana, Alaska, yield
average and extreme measurements as follows: Total length, 336
(310-350); length of tail, 93 (84-105); length of hind foot, 49
(45-51).

Female: Five adults, one each from Alatna River, mountains near
Eagle, Kamarkak in Alaska, Arctic Red River and Baillie Island in
Canada, yield average and extreme measurements as follows: Total
length, 285 (272-304); length of tail, 77 (68-95); length of hind
foot, 39 (34-43).

Weight of 5 subadult males from Tanana is 206 (163-248) grams;
adults would be heavier.

_Color._--Winter pelage all white except tip of tail. Summer
pelage with upper parts uniform in color and Raw Umber or darker
(16_n_) of Ridgway and about tones 2 to 3 of Chocolate of Oberthür
and Dauthenay, pl. 343, but in autumn some specimens have more
light red than tones 2 or 3. Underparts Sulphur Yellow, Colonial
Buff, or Primrose Yellow, often white on chin and insides of
forelegs; color of underparts extends narrowly over upper lips,
distally on posterior sides of forelegs onto antipalmar surface of
forefeet, onto proximal two-thirds or three-fourths of underside
of tail as length of tail is measured along tail-vertebrae, on
medial sides of hind legs to a point between knee and ankle but
reappears on antiplantar faces of toes and in some individuals is
narrowly continuous onto toes; rim of ear in some specimens with
short, white or pale hairs giving ears distinct whitish border;
least width of color of underparts averaging, in adult males from
Alaska, 65 (46-93) per cent of greatest width of color of upper
parts. Black tip of tail in 5 males in winter pelage from Tanana
averaging 84 (70-93) mm. which is 91 (75-107) per cent of length
of tail-vertebrae.

_Skull._--Male (based on 5 adult topotypes): See measurements and
plates 2-4. As described in _Mustela erminea richardsonii_ except
that: Weight, 3.5 (3.1-3.9) grams; basilar length 42.5
(41.8-43.3); length of tooth-rows more than length of tympanic
bulla; breadth of rostrum measured across lacrimal processes
averaging more than a third of basilar length; interorbital
breadth more than distance between glenoid fossa and posterior
border of external auditory meatus; zygomatic breadth more than
distance between last upper molar and jugular foramen.

Female (based on 2 adult topotypes and 2 adults and 4 subadults
from central Alaska): See measurements and plates 9-11. As
described in _Mustela erminea richardsonii_ except that: Weight,
1.5 (1.2-2.0) grams; basilar length, 35.7 (34.5-37.0); length of
tooth-rows more than length of tympanic bulla; breadth of rostrum
more than 30 per cent of basilar length; interorbital breadth more
than distance between glenoid fossa and posterior border of
external auditory meatus; zygomatic breadth more than distance
between last upper molar and jugular foramen (except in specimens
from Ellesmere Island where two distances are approximately
equal).

Cranial differences from _Mustela erminea kaneii_ (which occurs on the Asiatic side of Bering Strait), in both males and females, are: larger size relatively as well as actually, broader except in mastoidal region where relatively (to basilar length) the width is less; preorbital part of skull broader as well as longer.

From _kadiacensis_ differences in the skull of the male are: size less; 13 per cent heavier, relatively (to basilar length) narrower across interorbital region and zygomatic arches; tympanic bullae relatively as well as actually narrower. Judging by the single available adult female of _kadiacensis_, the skull of female _arctica_ is larger in all parts measured, a fourth heavier, has tympanic bullae of almost twice the volume and the interorbital and preorbital regions, relative to the braincase, are much reduced in whatever plane measured.

Differences from _richardsonii_, additional to those noted above in the formal description of the skull, between the males, are: larger in all parts measured except length of tympanic bulla which is about the same; 42 per cent heavier; relative to basilar length, skull broader with preorbital part longer as well as broader; tympanic bullae more inflated posteriorly. The same differences prevail between females except that the skull is 36 per cent heavier and in _arctica_ the length of the bulla is actually more (although relative to the basilar length less) and its greater inflation posteriorly is hardly perceptible. Differences from _alascensis_, additional to those indicated in the formal descriptions of the skulls of the two, in males, are: larger in every part measured; 95 per cent heavier; relative to the basilar length, skull broader with preorbital part longer as well as broader; measured at a point opposite the foramen lacerum anterius, the width of the pterygoid space is more, rather than less, than 40 per cent of its length. Excepting this difference in width of interpterygoid space, the same differences prevail between females, those of _arctica_ being 56 per cent heavier.

Comparison with _semplei_ is made in the account of that subspecies.

Skull indistinguishable from that of _polaris_.

_Remarks._--The person who studies specimens of this subspecies finds labels inscribed with the names of naturalists well known to all readers of literature on the Arctic. Sir John Franklin, R. McFarlane, R. Kennicott, E. W. Nelson and R. M. Anderson are names which appear commonly. Of Alaskan specimens prepared according to modern methods, a large share was obtained by O. J. Murie and L. R. Dice.

The ermine was observed in the far north by early explorers and was mentioned in the literature, almost always under the name then used for the ermine of northern Europe and Asia. In 1896 Bangs misapplied to it the name _richardsonii_ but Merriam in the same year corrected the application of this name and proposed as new for this weasel the name _arctica_, the name in use today. For almost 50 years after Merriam and Bangs wrote about it, _arctica_ was treated, nominally at least, as a species distinct from its other relatives in both the Old-and New-World. The subspecific status of _arctica_ was emphasized in 1944 (555) by the present writer in reporting in detail upon the specimens, of _Mustela erminea_, from Eastern Asia which were made available on loan by Professor B. S. Vinogradov and the late Anatol I. Argyropulo of the Leningrad Academy of Sciences. Specimens of _Mustela erminea kaneii_ from the Asiatic side of Bering Strait and _Mustela erminea arctica_ from the American side are distinguishable by slight cranial characters but in coloration and external measurements I can detect no differences. Merriam's (1896:16) mention of more golden-colored upper parts and darker underparts in American specimens than in _erminea_ was the result of his comparison of Alaskan and northern European specimens. When Old World specimens from eastern Siberia, instead of from Europe, are used the differences mentioned by Merriam do not apply. Incidentally, many Siberian specimens have the white border, on the ear, which Merriam (_loc. cit._) noted as a distinguishing feature of _arctica_. When Merriam named _arctica_ he said (1896:15, 16) "_Putorius arcticus_ . . . has heretofore been confounded with _erminea_ or _richardsonii_. . . . It is interesting to find in this country an Arctic circumpolar weasel which, though specifically distinct, is strictly the American representative of the Old World _erminea_." Bearing in mind that Merriam's concept of species and subspecies (see Merriam, 1919:6) differed from that of nearly all modern systematists it is clear from his statement quoted above that he correctly understood the zoölogical relationship obtaining between the ermines of the Old and New Worlds.

Ognev (1935:31) seems to have been the first to use the name combination _Mustela erminea arctica_ for Alaskan specimens. Thereby he expresses the view adopted here, namely that the American ermine is subspecifically but not specifically distinct from the Old World animal. Whether actual intergradation (crossbreeding) ever takes place across the narrow Bering Strait I do not know. I doubt that crossbreeding occurs but considering the Diomedes (islands), that might serve as a half way stopping point, and remembering Mr. Charles Brower's oral statement to me that he had seen tracks of ermine as far as 10 miles from the northern shore of Alaska out on the ice, the possibility must be granted of an occasional individual crossing from one side to the other of Bering Strait on the ice in winter or of being carried across when the ice broke up and drifted. If transfers of this kind occurred often one would expect ermines to occur also on Saint Lawrence Island where apparently they do not. The one skin (U. S. Nat. Mus. no. 259046) seen as labeled from there, my friend, Otto William Geist ascertained was imported as a skin with other furs from Siberia.

Ognev (_op. cit._) who used the name combination _Mustela erminea arctica_ for Alaskan specimens, applied it also to animals from Kamchatka. At the same time he recognized the animal from the eastern mainland of Siberia (as opposed to the peninsula of Kamchatka) under the name _Mustela erminea orientalis_ Ognev 1928. Hall (1944:556) applied the earlier proposed name _Putorius kaneii_ Baird 1857, to the animal on the eastern mainland of Asia and proposed the new name _Mustela erminea digna_ for the ermine of Kamchatka. In comparing material of these two Asiatic races with topotypes and other specimens of _M. e. arctica_ from Alaska, it seemed to me that the degree of relationship, one with the other, was about the same. _M. e. digna_ has a slightly larger preorbital region than _M. e. kaneii_, and the skull is longer. In both of these particulars _digna_ approaches closer to _arctica_. _M. e. kaneii_ has longer tympanic bullae and a wider skull than _digna_ and therein approaches more towards _arctica_ than toward _digna_. As nearly as I can make out, _digna_ and _kaneii_ show a nearly equal degree of resemblance to _arctica_. Also the degree of difference between _digna_ and _kaneii_ is about the same as between either one of them and _arctica_. In view of the above considerations the ermines of the New and Old worlds are here regarded as only subspecifically distinct.

In the original description of _Putorius audax_ (here regarded as inseparable from _Putorius arcticus_ Merriam) Barrett-Hamilton erroneously designated the type locality as "Discovery Bay, North Greenland" whereas he should have written Grinnell Land [= Ellesmere Island of modern terminology] in place of Greenland. As reference to Nares (1877 and 1878) will readily reveal, Discovery Bay is near 65° W and 81° 40´ N, across Robeson Channel, to the west, from Greenland. The label on the type specimen and the specimen register in the British Museum of Natural History each designates the locality for this specimen, the type of _audax_, as Discovery Bay without mention of Greenland. The published accounts of Feilden (1878) and Nares (1877 and 1878) state that specimens of ermine were obtained at Discovery Bay. Probably H. C. Hart is the collector of the specimen; he was the naturalist attached to H. M. S. Discovery which wintered at Discovery Bay while H. W. Feilden was the naturalist attached to H. M. S. Alert which wintered a few miles southeast of Cape Sheridan, also on the eastern coast of Ellesmere Island.

It is true that from these ships a trip was made into Greenland and an ermine (only one individual it seems) was obtained there, but this individual was the type specimen of _Mustela erminea polaris_, in the account of which race something of the history of this specimen is given.

With the material available--and it is not entirely adequate--I can detect no features by which animals from the type locality of _audax_ can be distinguished from typical _arctica_ which latter name has priority.

Intergradation with _richardsonii_ probably occurs completely across the continent. Intergrades here referred to _arctica_ include those from Fort Goodhope. The one defective specimen from Lake Lebarge, Yukon, is not certainly identified as _arctica_ and how far west of Teslin Lake the boundary-line between _arctica_ and _richardsonii_ should be drawn remains to be ascertained. The one specimen available from Hinchenbrook Island, no. 912 Mus. Vert. Zoöl., an adult female, is doubtfully referred to _arctica_ because the damaged tympanic bullae appear to be no larger than in _alascensis_, and the size of the skull is more as in _alascensis_ although intermediate between that race and _arctica_. Shape of the skull is more as in _arctica_. Possibly more nearly adequate material would show the existence on Hinchenbrook Island of an insular race differing in about the same degree from _arctica_ of the mainland as does the insular _kadiacensis_. Nevertheless, the males from farther south at Cape Yakataga are in all respects _arctica_ and this argues against near relationship to _alascensis_ of the animal on Hinchenbrook Island. The three animals seen from Yakutat Bay are so young as not to display clearly the cranial characters of the subspecies but the extension of the color of the underparts onto the underside of the tail in them and also in the skin without corresponding skull from Glacier Bay, Alaska, is as in _arctica_, the race to which they are referred, and gives substantial basis for showing the geographic range of _arctica_ as extending this far south along the Pacific Coast.

_Specimens examined._--Total number, 281, arranged alphabetically
by Districts and from north to south in each District. Unless
otherwise indicated, specimens are in the collection of the United
States National Museum.

=Alaska.= Point Barrow, 22 (1[1], 1[2], 1[75], 4[1], 7[60], 6[74]);
Flaxman Island, 3; Collinson Point, 1[77]; Salirochet River,
1[77]; Hulahula River, 1[2]; 69°20´ & 141°, 1; Rampart House, 1;
Yukon River, mouth of Porcupine River, 18; Alatna River, 30 mi.
from mouth, 1; Koyakuk Riv., 16 mi. below Bettles, 4; Shelton,
1[75]; Kruzamepa, 1[75]; Tanana, 6; Boulder Creek, Chena River, 3;
Fort Reliance, 4; Yukon River, 20 miles above Circle, 2; Mts. near
Eagle, 42 (1[60]); Snake River, Nome, 1[9]; Nulato, 3;
No[e]wikakat Riv., 1; Kantishna, 3; Fairbanks, 5 (1 20 mi. E and 1
33 mi. E); Richardson, 1; N. Fk. Kuskokwim R. at base of Mt.
Sischo, 1; N. Fk. Kuskokwim R. at Junction with McKinley Fk., 1;
Nenana Riv., mouth of Maurice Cr., 1; Ober Cr., trib. of Jarvis
Cr., Delta Riv. region, 1; head of Savage Riv., near Jennie Cr.,
1; Wonder Lake, 1[74]; Bear Cr., 3; Unlakleet, 3; St. Michaels,
11; 125 mi. E and a little N of Knik, Cook Inlet, on S side
Matanuska Range, 1[60]; Hope, Cook Inlet, 1; Iak Lake, 1[68]; head
of Behring Riv., 1; Bethel, 2; Kenai Lake, 8; Kenai Peninsula, 13
(2[2]); He[i]nchenbrook Island, 1200 ft., 1[74]; Sunshine Point,
Kaliekh River, Yakataga Dist., 1[8]; Cape Yakataga, 3[8]; Yakutat
Bay, 3[74]; Seward, 7; Seldovia, 22 (4[2]); Homer, 1[2]; Cape
Elizabeth, 18; Akchookuk Lake, 1; Lake Weelooluk, 1; Kokwok Riv.,
80 mi. up, 4; Nushagak, 1; Nushagak Riv., 1; Kolukuk, 1; Egooshik
River at mouth, 1; Glacier Bay, 1; Becharof Lake, between Portage
Bay and Becharof Lake, 1; Ugashik Riv., 4; Chignik, 7; East base
Frosty Peak, 1; Pavlov Bay, 1[100]; Mt. Pavlof, 1[75]; Unimak
Island, 2 (1[75]).

=District of Franklin.= Cape Sheridan, 1[2]; Discovery Bay,
Ellesmere Island, 1[7] (type specimen of _Putorius audax_
Barrett-Hamilton); Axel Heiberg Island, 1[95]; Bache Peninsula,
Ellesmere Island, 1[77]; Bedford Pims Island, 4[75]; Craig Harbor,
2[77]; Cape Kellett, Banks Island, 1[77]; Franklin Isthmus, 1[95];
King William Island, 2[95].

=District of Keewatin.= Ualiak, Ogden Bay, 2[95].

=District of Mackenzie.= Baillie Island, 1[75]; Franklin Bay, 1;
Langton Bay, arm of Franklin Bay, 15 mi. S of, 1[2]; Cockburn
Point, 69°N, 115°W, 2[77]; Dolphin and Union Strait, 1[77];
Bernard Harbor, 2[77]; Kent Peninsula, 4[95]; Horton Riv., near
Fort Anderson, 1; Fort Anderson, 6; Anderson River, 3; Barry
Island, Bathurst Inlet, 1[77]; Fort McPherson, 1; Peels River, 2;
Arctic Red River, 8[75]; Fort Good Hope, 6; Clinton Colden, 1[2].

=Yukon.= Kamarkak, 1[77]; Herschel Island, 1[75]; Lapierres House,
2; Forty Mile, L. T. Coal Cr., 4[74]; head of Coal Cr., 1;
Macmillan River, Forks, 1; 20 mi. W. Ft. Selkirk, 1; Slims River,
near Kluane, 1[75]; head of Lake Lebarge, 1.

=Mustela erminea polaris= (Barrett-Hamilton)

Ermine

_Putorius arcticus polaris_ Barrett-Hamilton, Ann. and Mag. Nat.
Hist., 13 (ser. 7):393, May, 1904.

_Mustela erminea_, Manniche, Meddelelser on Grønland, 45:80-85, 1
fig., 1910.

_Mustela arctica polaris_, Miller, U. S. Nat. Mus. Bull., 79:97,
December 31, 1912.

_Mustela erminea polaris_, Hall, Journ. Mamm., 26:179, July 19,
1945.

_Type._--Probably female, skin only; no. 78. 6. 19. 11, Brit. Mus.
Nat. Hist.; Gap Valley, 7-1/4 miles northeast Cape Brevoort, 82°
N, 59° 20´ W, Northwestern Greenland; June 15 or 16, 1876;
obtained by Lewis A. Beaumont.

The skin is in full, fresh summer pelage, fairly well stuffed
except for the tail which is unstuffed; the whole is in a good
state of preservation.

_Range._--North coast, and east coast as far south as Turner Sound
(between 69 and 70 degrees) of Greenland. See figure 25 on page
95.

_Characters for ready recognition._--Differs from _M. e. arctica_
in lighter upper parts (near [_j_] Buckthorn Brown rather than Raw
Umber or darker) and more intensely-colored underparts that are
Buff Yellow rather than Sulphur Yellow, Colonial Buff, or Primrose
Yellow; from _M. e. semplei_ in color in same fashion as from
_arctica_ and in larger size of skull.

_Description._--_Size._--Male: One subadult and two adults (one
ad. from Scøresby Sound and other two from Ymer Island) measure as
follows, the average being given first: Total length, 318 (301,
320, 315); length of tail, 72 (69, 70, 73); length of hind foot,
46.5 (44, 46, 47).

Female: No measurements taken in the flesh available but hind
foot, measuring 33.5 in the dried state and therefore
approximately 35 in life.

_Color._--As described in _Mustela erminea arctica_ except that
upper parts in summer near (_j_) Buckthorn Brown and tone 4 of
Dark Fawn of plate 307 to tone 1 of Raw Umber of plate 301 of
Oberthür and Dauthenay. Underparts Buff-Yellow. Least width of
color of underparts averaging, in 3 males, 66 (57-72) per cent of
greatest width of color of upper parts. Black tip of tail in same
males averaging 71 (70-72) mm. which is 99 (99-104) per cent of
length of tail-vertebrae.

The lighter-colored upper parts and more intensely yellow
underparts are the distinguishing features of the subspecies
_polaris_ in comparison with other races of American _M. erminea_.

_Skull._--Male (based on 5 adults from eastern Greenland): See
measurements. As described in _Mustela erminea richardsonii_
except that: Weight more (not recorded); basilar length, 41.3
(39.0-42.4); length of tooth-rows more than length of tympanic
bulla; breadth of rostrum measured across lacrimal processes
averaging more than a third of basilar length; interorbital
breadth more than distance between glenoid fossa and posterior
border of external auditory meatus; zygomatic breadth more than
distance between last upper molar and jugular foramen.

Female (based on 2 adults, Turner Sund and Kap Hoeg): See
measurements. As described in _Mustela erminea arctica_ except
that basilar length 36.8 (35.9, 37.8), and length of tooth-rows
not more than length of tympanic bulla. Skulls of females not in
hand when this comparison is written; only the recorded
measurements are available.

To me the skull of _polaris_ is indistinguishable from that of _arctica_. Therefore the comparisons made of the skull of _arctica_ with those of other subspecies will apply also for _polaris_.

_Remarks._--In view of the heretofore erroneous assignment of the type locality of _Mustela erminea audax_ to Greenland, pains were taken to verify the statement by Barrett-Hamilton (1904:393) relative to the type specimen of _polaris_. Taking pains thus seemed the more worthwhile because in the specimen register at the British Museum of Natural History, there is written to the right of catalogue numbers 78-6 = 19 nos. 1-11, "Discovery Bay Presented by Mr. Hart Arctic Collection." This refers to no. 78.6.19.1. There are no ditto marks below but by implication this data applies also to nos. 1-11, which include the holotype of _polaris_. A label attached to the specimen does however give the locality as "Hall Land" "N Greenland" and another label has on it "Ermine, procured by Mr. Beaumont Greenland Lat 89° Long W 59-20." The 89° is obviously a mistake (on the label or in my transcription of it) for 82°.

Reference to Nares (1877:385) reveals that Lieutenant Lewis A. Beaumont, under date of June 15 and 16, 1876, wrote in his field journal as follows: "I shot an ermine." In the daily accounts of his journey from Discovery Bay on Grinnell Land [= Ellesmere Island], across Robeson Channel and along the north coast of Greenland to the west base of Mount Farragut near 50° 30´ W he mentions the ermine only this once. For several other kinds of animals, Beaumont mentions individuals seen or shot, often with the notation that this is the second, or third seen. This mention of a kind of animal whenever seen was in accordance with orders. On page 39 of the Discovery Report (_op. cit._, 1877) in "General orders to sledging parties" by Captain G. S. Nares, Commanding the Expedition, we find ". . . note daily: IV State the animals seen and those shot." Reference to the map facing page 358 of the (_op. cit._) report reveals that on the 15th and 16th, camps were made by Beaumont in Gap Valley, each 7-3/4 miles northeast of Cape Brevoort, one camp on either side of the 82° line, and separated from each other by a distance of only 2-1/4 air line miles or 4-1/2 miles march according to his journal.

These several data, then, are the bases for designating the type locality of _M. e. polaris_, in the way that I have stated it at the beginning of this account of the subspecies.

The light-colored upper parts and more intensely yellow underparts well differentiate this subspecies from _arctica_ or _semplei_. Intergradation is suggested by a skin, no. 1462, Copenhagen Zoological Museum, from Axel Heibergs Land, the color of the underparts of which agrees with that of specimens from Greenland. Also the color of the upper parts is decidedly nearer that of animals from Greenland than to that of specimens from Ponds Inlet, Tulican and Gifford River. No other specimens west or south of Greenland suggest intergradation. In Greenland itself, one adult, a female from Turner Sund, East Greenland, has the underparts no more yellowish than in some specimens from Melville Peninsula. This female is darker on the back than any one of the other 10 specimens from Greenland in summer pelage examined at the same time, but even so is not so dark colored as animals from Baffin Island or other islands to the west of Greenland.

The final summation of information about this subspecies would have been more precise if I had been able to have actually in hand, at the time of writing, specimens preserved in the Copenhagen Zoological Museum. The war made it impractical to secure the loan of these as previously planned. Even so, the measurements and notes on color that I obtained from this material, in 1937, in Copenhagen, suffice to prove that the subspecies _polaris_ is well set off in color from the other American subspecies of _Mustela erminea_.

The best material of this subspecies is in the University Zoological Museum at Copenhagen, Denmark.

_Specimens examined._--Total number, 35, arranged by locality from
the western end of the north coast of Greenland, eastward and then
southward down the east coast. Unless otherwise indicated,
specimens are in the Universitetets Zoologisk Museum, Købnhavn,
Danmark.

Gap Valley, 7-1/4 mi. NE Cape Brevoort, 82 N, 59 20´ W, 1 (British
Mus.); Dragon Point, 1; Danmarks Havn (Fjeldene ved Baadskjeret,
1; lille Fjeld, 1; Lyservig, 1; harefjeldets, 4; Rypefjeldet, 1;
Baadskjeret, 1; Danmarkshavn, 3) 12; Christians Havn, 1 (not found
on map); Shannon Island, 4; Germania Havn, 2; Claveringoen, 1;
Carls Havn, 1; Myggbukta, 2 (British Mus.); Ymer[s] Island, 2
(Mus. Comp. Zool.); Kap Hoegh, Jamesonsland, 1 (Berlin Zool.
Mus.); Scoresby Sund, 3; Turner Sund, 4.

=Mustela erminea semplei= Sutton and Hamilton

Ermine

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

_Mustela arctica semplei_ Sutton and Hamilton, Ann. Carnegie Mus.,
21:79, February 13, 1932.

_Mustela arctica labiata_ Degerbøl, Rept. 5th Thule Exped., 2 (no.
4):25, 1935, type from Malugsitaq, Melville Peninsula, Canada.

_Mustela erminea semplei_, Hall, Journ. Mamm., 26:179, July 19,
1945.

_Type._--Male, subadult, skull and skin; no. 6470, Carnegie Mus.;
Coral Inlet, South Bay, Southampton Island, Canada; October 8,
1929; obtained by George Miksch Sutton, original no. 3M.

The skull has two holes in it: one is immediately above the left
canine, and the other (2 × 5.5 mm.) is 3 millimeters to the left
of the median line at the juncture of the frontal and parietal
bones. From this last mentioned hole a fracture extends back
halfway to the lambdoidal crest. The tip of the left upper canine
is broken off. Otherwise the skull is complete, and the teeth all
are present and entire. The skin is well made and in fresh white
winter pelage except for a trace of the old brown summer pelage on
the back, on the tail, on the anterior borders of the ears, and in
a spot 11 mm. long and 8 mm. wide on the nose.

_Range._--Baffin and Southampton islands, Melville Peninsula and
west side of Hudsons Bay as far south as Eskimo Point. See figure
25 on page 95.

_Characters for ready recognition._--Differs from _M. e. arctica_,
in that, in males, hind foot less than 44 and basilar length less
than 41 and in that females average smaller, their skulls being
only about 10 per cent lighter; from _M. e. polaris_ in darker
upper parts (Raw Umber rather than Buckthorn Brown) and
less-intensely-colored underparts that are Sulphur Yellow,
Colonial Buff or Primrose Yellow rather than Buff Yellow, and in
lesser size in the same fashion as from _arctica_; from _M. e.
richardsonii_, of both sexes, in that proximal two-thirds of under
side of tail colored same as underparts rather than same as upper
parts and by least interorbital breadth amounting to more, instead
of less, than distance between glenoid fossa and posterior border
of external auditory meatus.

_Description._--_Size._--Male: Ten adults and subadults, from
Southampton Island, yield average and extreme measurements as
follows: Total length, 282 (267-318); length of tail, 77 (59-87);
length of hind foot, 40 (38-43).

Female: Four subadults from Southampton Island yield average and
extreme measurements as follows: Total length, 271 (256-288);
length of tail, 71 (69-74); length of hind foot, 35 (33-38).

_Color._--As described in _M. e. arctica_ except that least width
of color of underparts averaging, in 7 males, 59 (45-81) per cent
of greatest width of color of upper parts. Black tip of tail in 19
male topotypes averaging 72 (64-83) mm. which is 91 (75-122) per
cent of length of tail-vertebrae.

_Skull._--Male (based on 2 adults and 10 subadults from
Southampton Island): See measurements and plates 2-4. As described
in _Mustela erminea richardsonii_ except that: Weight, 2.0 (in one
subadult) grams; basilar length, 37.5 (35.7-39.9); length of
tooth-rows more than length of tympanic bulla; breadth of rostrum
more than a third of basilar length; interorbital breadth more
than distance between glenoid fossa and posterior border of
external auditory meatus; zygomatic breadth more than distance
between last upper molar and jugular foramen.

Female (based on 1 adult and 4 subadults from Southampton Island):
See measurements and plates 9-11. As described in _Mustela erminea
richardsonii_ except that: Weight, 1.35 (in one adult) grams;
basilar length, 34.2; breadth of rostrum more than 30 per cent of
basilar length; interorbital breadth more than distance between
glenoid fossa and posterior border of external auditory meatus;
zygomatic breadth more or less than (approximately same as)
distance between last upper molar and jugular foramen.

In comparison with _richardsonii_, the skulls of males averaged smaller in every measurement taken except breadth of rostrum and interorbital breadth which are more, and zygomatic breadth and length of inner lobe of M1 which are approximately the same; skull about 20 per cent lighter; in relation to basilar length, preorbital region longer and broader in every part measured. Female averages larger, in every part measured; 23 per cent heavier; in relation to basilar length, every other measurement more. It is noteworthy that the skull of the male is smaller and the skull of the female larger than in _richardsonii_.

Differences from _arctica_ are: Size less, in each sex; males about 40 per cent and females 10 per cent lighter; in males, skull more rounded in outline as viewed from above because zygomatic arches arise less abruptly from skull; in males tympanic bullae do not project so far ventrally from squamosal floor of braincase; with these exceptions, skull of _semplei_ can be said to be a smaller edition of that of _arctica_.

From _polaris_, _semplei_ differs, cranially, in the same way as from _arctica_.

_Remarks._--There is a slight increase in size of ermines toward the north which probably is the result of intergradation between _semplei_ and _arctica_. Specimens from the northern part of Baffin Island are larger than those from farther south. Specimens from the mainland west of Southampton Island may owe their smaller (than in _arctica_) size to intergradation with _richardsonii_ almost as much as to intergradation with _semplei_.

Degerbøl's name _Mustela arctica labiata_ was applied to specimens, which to me are indistinguishable from topotypes of _Mustela arctica semplei_, which latter name has three years priority. Degerbøl (1935:34) states that Malugsitaq, Melville Peninsula, is the type locality. He did not designate a type specimen. Reference to his account (_op. cit._:26) shows that he lists five specimens from the type locality, or more precisely as "Malugsitaq, Lyon Inlet. 5 summer skins. [M] [M] June-July 1922. P. F., CN. 2262-2266." On labels attached to these specimens, "Lyon Inlet" is replaced with "Melville Peninsula." On July 28, 1937, Degerbøl and I together examined these specimens in his laboratory. Because no. 2262 is first mentioned I regard it as the type. It is a juvenal male, skull and skin, no. 2262 (20.5 1931.8), Univ. Zool. Mus. Copenhagen, obtained in June or July of 1922 by Peter Freuchen whose original number was / s 2324. The specimen is one of 5 males taken at the same locality by the same collector and they bear identical data as to date. They look to be of the same litter for all are roughly of the same size and each retains milk teeth.

Additional females, with external measurements carefully taken, are much needed from Southampton Island, because the available females are insufficient to show the degree of sexual dimorphism. If the meager data available be accepted, the difference in size between the two sexes is less than in other subspecies. My own feeling is that a better sample of females would show the secondary sexual difference in size to be more than available data indicate.

_Specimens examined._--Total number, 183, arranged from north to
south by islands, or regions attached to the mainland, and from
north to south in each region or island. Unless otherwise
indicated, specimens are in the Zoological Museum, University of
Copenhagen, Denmark.

=Baffin Island.= Pond[s] Inlet, 8; (5[77]); Tulukan (sometimes
spelled Tulukat), 6; Cape Eglinton, 1[7]; Gifford River, 2; Clyde,
3[86]; head of Cumberland Sound, 1[91]; Pangnirtung, 2[77];
Kingnait Fiord, 1[91]; Kikkulin Island, Cumberland Sound, 1[7];
Blacklead Island, Cumberland Gulf, 1; merely Cumberland Gulf,
1[7]; merely east Baffin Island, 34[7]; Cape Dorset, 2[2]; SW
coast of Baffin Island, 1[75].

=Melville Peninsula.= Iglulik, 3; Pingerqalik, 2; Kingadjuaq,
Amitsog, 3; Rae Isthmus, 3; Lyons Inlet, 13(9[2]); M[N?]
alugsitaq, Lyon Inlet, 5; Itibdjeriang, 2; Repulse Bay, 27 (22[2],
2[19]); Drichetts Cove, Hurd Channel, 1[2]; Gore Bay, 1; Haviland
Bay, 1; Cleveland Harbor, Frozen Strait, 1.

=Southampton Island and adjacent islands.= Danish Island, 11;
Vansittart Island, 4. Southampton Island: Coral Inlet, 19 (1[77],
18[9]); Prairie Point, 1[9]; Munnimunnek Point, South Bay, 5[9];
Native Point, 1[9]; Ranger Rim, 1[9]; Koodloatok (not found on
map), 1[77]; merely Southampton Island, 1[77]; Gore Bay, 1[2]; Fox
Channel, 2[2].

=Mainland to west of Southampton Island.= Cape Fullerton, 3
(1[77], 2[2]); Chesterfield Inlet, 4 (1[77], 1[9]); Tavane, 1[77];
N of Wagner Inlet, 1; Eskimo Point, 1[86].

=Mustela erminea kadiacensis= (Merriam)

Ermine

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

[_Putorius arcticus_] subspecies _kadiacensis_ Merriam, N. Amer.
Fauna, 11:16, June 30, 1896.

_Putorius kadiacensis_, Preble, Proc. Biol. Soc. Washington,
12:169, August 10, 1898.

_Mustela kadiacensis_, Miller, U. S. Nat. Mus. Bull., 79:97,
December 31, 1912.

_Mustela erminea kadiacensis_, Hall, Journ. Mamm., 26:179, July 19,
1945.

_Type._--Male, subadult, skull and skin; no. 65290, U. S. Nat.
Mus., Biol. Surv. Coll.; Kodiak Island, Alaska; April 25, 1894;
obtained by B. J. Bretherton, original no. 304.

The skull lacks the basioccipital, part of the basiphenoid, the
occipital region on the right side and the posterior part of the
right tympanic bulla. The third, upper, left incisor is missing.
Otherwise the teeth all are present and entire.

The white, winter skin is only moderately well stuffed but in a
good state of preservation. The spring coat is appearing along the
back. This coat is visible at only two places unless the hair be
parted when the new brown pelage, which is coming in, can be seen
all along the midline of the back.

_Range._--Kodiak Island, Alaska. See figure 25 on page 95.

_Characters for ready recognition._--Differs from _M. e. arctica_
in hind foot less than 33 in females and in zygomatic breadth
amounting to less, instead of more, than distance between last
upper molar and jugular foramen irrespective of sex.

_Description._--_Size._--Male: One adult and 3 subadults yield
average and extreme measurements as follows: Total length, 341
(318-360); length of tail, 93 (86-102); length of hind foot, 47
(44-49).

Female: An adult measures: Total length, 258; length of tail, 70;
length of hind foot, 31.

_Color._--As described in _M. e. arctica_, except that least width
of color of underparts averaging 54 (40-83) per cent of greatest
width of color of upper parts. Black tip of tail in 3 males in
summer pelage averaging 80 (70-90) mm. which is 85 (69-96) per
cent of length of tail-vertebrae.

_Skull._--Male (based on 2 adults): See measurements and plates
2-4. As described in _Mustela erminea richardsonii_ except that:
Weight 3.1 grams; basilar length, 42.6 (42.1-43.2); length of
tooth-rows more than length of tympanic bulla; breadth of rostrum
measured across lacrimal processes averaging more than a third of
basilar length; interorbital breadth more than distance between
glenoid fossa and posterior border of external auditory meatus.

Female (based on one adult, no. 98042): See measurements and
plates 9-11. As described in _Mustela erminea richardsonii_ except
that: Weight, 1.2 grams; basilar length, 33.0; length of
tooth-rows more than length of tympanic bulla.

Comparison with _arctica_ has been made in the account of that subspecies. Although _richardsonii_ and _kadiacensis_ are described as having the zygomatic breadth less than the distance between the last upper molar and jugular foramen, the zygomatic breadth is considerably more in _kadiacensis_ than in _richardsonii_; consequently the two dimensions are more nearly equal than in _richardsonii_. Except for being slightly narrower, the skull of _kadiacensis_ is only a slightly smaller edition of that of _arctica_.

_Remarks._--When naming the weasel from the mainland of Alaska as new, under the name _Putorius arcticus_, Merriam (1896:16) wrote: "A small form of _arcticus_ occurs on Kadiak Island. . . . It is probably worthy of recognition as subspecies _kadiacensis_." The informality of this description possibly was in part due to the describer's recognition of the fact that the degree of difference between _arcticus_ and the insular _kadiacensis_ was slight. Specimens collected after Merriam proposed the name for the weasel of Kodiak Island show the animal there to be less different from _arctica_ of the adjacent mainland than he thought; small size is the most pronounced distinction of _kadiacensis_ and Merriam's male type specimen is smaller than any of the five additional males saved from Kodiak Island since that time. Even so the differences fully warrant subspecific recognition, in my opinion, although _kadiacensis_ is not a strongly differentiated race. More adult females are needed to ascertain the norm of form and size for that sex. If the one female known is typical, the difference from _arctica_ is more pronounced in females than in males. The lesser size of _kadiacensis_ can hardly be credited entirely to the effect of insularity, for animals from the southern part of the mainland, on Kenai Peninsula for example, are smaller than those from central and northern Alaska and provide evidence of intergradation of a sort between _kadiacensis_ and _arctica_.

_Specimens examined._--Total number, 9, all from Kodiak Island,
Alaska, and unless otherwise indicated in the U. S. National
Museum.

Karluk, 1 (Stanford Univ.); Kodiak, 7; Kodiak Island, 1 (Field
Mus. Nat. Hist.).

=Mustela erminea richardsonii= Bonaparte

Ermine

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

_Mustela richardsonii_ Bonaparte, Charlesworth's Mag. Nat. Hist.,
2:38, 1838.

_Putorius cicognanii_, Baird, Mamm. N. Amer., p. 161, 1858 (part).

_Putorius richardsonii_, Baird, Mamm. N. Amer., p. 164, 1858
(part-Halifax, N. S.).

_Putorius_ (_Gale_) _erminea_, Coues, Fur-bearing animals, p. 109,
1877 (part).

_Putorius richardsoni_, Bangs, Proc. Biol. Soc. Washington, 10:16,
February 25, 1896.

_Putorius cicognani richardsoni_, Merriam, N. Amer. Fauna, 11:11,
June 30, 1896.

_Putorius (Arctogale) cicognanii cicognanii_, Bangs, Proc. New
England Zoöl. Club, 1:18, February 28, 1899.

_Putorius microtis_ Allen, Bull. Amer. Mus. Nat. Hist., 19:563,
October 10, 1903. Type from Shesley, British Columbia.

_Putorius arcticus imperii_ Barrett-Hamilton, Ann. and Mag. Nat.
Hist., 13(ser. 7):392, May, 1904. Type from Fort Simpson,
Mackenzie, Canada.

_Putorius cicognanii richardsoni_, Preble, N. Amer. Fauna, 27:231,
October 26, 1908.

_Mustela microtis_, Miller, U. S. Nat. Mus. Bull., 79:96, December
31, 1912.

_Mustela cicognanii mortigena_ Bangs, Bull. Mus. Comp. Zoöl.,
54:511, July, 1913. Type from Bay St. George, Newfoundland.

_Mustela cicognanii_, Sheldon, Journ. Mamm., 13:201, August 9,
1932.

_Mustela cicognanii richardsonii_, Miller, U. S. Nat. Mus. Bull.,
79:95, December 31, 1912; Hall, Univ. California Publ. Zoöl.,
40:368, November 5, 1934.

_Mustela cicognanii cicognanii_, Hall, Canadian Field-Nat., 52:108,
October, 1938.

_Mustela erminea richardsonii_, Hall, Journ. Mamm., 26:77, February
27, 1945; Hall, Journ. Mamm., 26:180, July 19, 1945.

_Type._--Male, age unknown, skin; no. 43.3.3.4, British Museum of
Natural History; probably from Fort Franklin, Canada; presented to
British Museum on or before March 3, 1843; may be the type.

In September, 1937, when I searched in the British Museum for the
skull, I found no trace of it nor mention of it in catalogues. The
skin is in white, winter pelage, mounted on a pedestal. See under
remarks for _Mustela e. cicognanii_ for reasons for and reasons
against regarding this specimen as the holotype.

_Range._--Hudsonian and Canadian life-zones of the greater part of
Canada from the Atlantic to the Pacific. See figure 25 on page 95.

_Characters for ready recognition._--Differs from _M. e. arctica_,
_polaris_, _semplei_ and _haidarum_, in both sexes, by proximal
two-thirds of under side of tail colored same as upper parts
rather than same as underparts, and interorbital breadth less,
rather than not less, than distance between glenoid fossa and
posterior border of external auditory meatus; from _M. e. bangsi_,
in that, in both sexes, least width of color of underparts
averages two-fifths rather than about a third of greatest width of
color of upper parts, and in that skulls of males are a fourth
heavier, basilar length averaging more than 40; from _M. e.
cicognanii_, in both sexes, in that least width of color of
underparts averages two-fifths instead of less than a third of
greatest width of color of upper parts, in females by 20 per cent
heavier skull (1.1 versus 0.92), in males by skull more, rather
than less, than 1.9 grams, and basilar length more, instead of
less, than 38; from _M. e. invicta_, in males, by skull more,
instead of less, than 1.9 grams; mastoid breadth more, instead of
less, than 19.9 mm.; depth of skull at anterior margin of
braincase more, instead of less, than 12.4 mm.; in females, by
same measurement of depth more, instead of less, than 10.1, and
weight of skull averaging more, instead of less, than one gram;
from _M. e. fallenda_ in both sexes upper lips white rather than
brown, in males, hind foot more than 41, basilar length more than
38.3, in females hind foot more than 29, basilar length more than
31.4, and breadth of rostrum amounting to less, instead of more,
than 30 per cent of basilar length; from _M. e. alascensis_ in
males in that black tip of tail more than 43, total length more
than 320, tympanic bullae more than 14 and longer than tooth-row
rather than less than 14 mm. and sometimes shorter than tooth-row,
females not individually distinguishable.

_Description._--_Size._--Male: Four adults (Fort Franklin, Fort
Simpson, Mts. W Fort Nelson, and Govt. Hay Camp, Wood Buffalo
Park) yield average and respective measurements as follows: Total
length, 331 average (340, 325, 330, 328); length of tail, 93 (102,
91, 93, 87); length of hind foot, 45 (48, 43, 45, 44). Weight of 4
adults from the Belcher Islands is 175 (135-180) grams. Of 10
subadults from Belcher Islands it is 119 (92-137) grams.

Female: Three adults from Great Slave Lake (Willow River,
Fairchild Point, and Fort Resolution) yield average and respective
measurements as follows: Total length, 252 (237, 238, 282); length
of tail, 69 (63, 60, 85); length of hind foot, 32 (31, 32, 34).
Corresponding, average measurements for three adults from Glacier
Lake are 240, 60, 32 and for 3 adults from the Athabasca Delta,
243, 65, 30. Weight of 8 subadults from the Belcher Islands is 69
(64-78) grams. Weight of adults would be more.

_Color._--Winter pelage all white except tip of tail. Summer
pelage with upper parts uniform in color and darker (16_n_) than
Raw Umber, and about tones 3 to 4 of Chocolate of Oberthür and
Dauthenay, pl. 343. Underparts Sulphur Yellow, Colonial Buff, or
Primrose Yellow, often nearly white on chin and insides of
forelegs; color of underparts extends narrowly over upper lips,
distally on posterior sides of forelegs onto antipalmar faces of
toes and sometimes over most of antipalmar surfaces of forefeet,
on medial sides of hind legs to a point between knee and ankle but
reappears on antiplantar faces of toes and in some individuals is
narrowly continuous onto toes. Least width of color of underparts
averaging, in a series of 12 males from the Athabasca Lake Region,
40 (25-54) per cent of greatest width of color of upper parts.
Black tip of tail averaging 56 (45-63) mm. in 5 adult males from
same region and thus 60 (48-70) per cent of length of
tail-vertebrae.

From _arctica_, _polaris_, _semplei_ and _kadiacensis_,
_richardsonii_ differs in: Color darker; ventral side of tail same
color as upper parts; light-colored underparts a fifth narrower;
black tip of tail by actual measurement a fifth shorter and
averaging less than two-thirds rather than more than four-fifths
of length of tail-vertebrae. From _cicognanii_, _richardsonii_
differs in that the underparts are a fourth wider and in some
specimens more brightly colored. The width of the underparts is
likewise a fourth more than in _bangsi_. In _invicta_ the
underparts are not so brightly colored as in some specimens of
_richardsonii_. From _fallenda_, _richardsonii_ differs in that
the upper parts often are lighter colored, upper lips white rather
than colored like upper parts, and underparts as wide again. In
comparison with _alascensis_, the black tip of the tail averages
three-fifths rather than a half of length of tail-vertebrae.

_Skull._--Male (based on 6 adults from 3 miles south of Big
Island, Great Slave Lake): See measurements and plates 2-4;
weight, 2.5 (2.1-2.9) grams; basilar length, 40.9 (39.6-43.7);
length of tooth-rows less than length of tympanic bulla; breadth
of rostrum measured across lacrimal processes less than a third of
basilar length; interorbital breadth less than distance between
glenoid fossa and posterior border of external auditory meatus;
zygomatic breadth less than distance between last upper molar and
jugular foramen.

Female (based on 4 adults: from Willow River, 1; Fort Resolution,
1; Athabasca Delta, 2; and 2 subadults, one from 3 mi. S Big
Island and one from 15 mi. above Smith Landing): See measurements
and plates 9-11; weight, 1.1 (0.9-1.4) grams; basilar length, 33.1
(31.5-34.2); length of tooth-rows less than length of tympanic
bulla; breadth of rostrum 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
less than distance between last upper molar and jugular foramen.

The skull of the female averages 56 per cent lighter than that of
the male.

Comparison of the skull with that of _arctica_, _polaris_, _semplei_, _kadiacensis_, _haidarum_, _cicognanii_, _bangsi_, _invicta_, _fallenda_, and _alascensis_ is made in the accounts of those subspecies.

_Remarks._--_M. e. richardsonii_ has the most extensive geographic range of any American race of _erminea_, is centrally located with respect to the other races, is more abundantly represented by study specimens in zoölogical collections than any other race, and is a sort of average for the species as a whole in most structural features. Therefore _richardsonii_ is used as a standard of comparison and accordingly is more fully described than any one of the other races each of which by reference to _richardsonii_ is described in comparative fashion. This comparative description has the virtue of more clearly indicating differences between subspecies and also makes for brevity.

John Richardson, Bernard R. Ross, and names of their companions, as written on the labels of the older specimens recall to the student's mind early explorations of the north country. Edward A. Preble obtained important specimens at several places and in recent years J. Kenneth Doutt and G. G. Goodwin have made the reviser's work easier by preparing specimens in series from areas not previously well represented.

The nomenclatural history of this subspecies begins with references in the literature that identify the animal as the Old World species, _Mustela erminea_--an identification which the study here reported upon shows to have been correct in the specific, although not in the subspecific, sense. Richardson, for example, in his "Fauna Boreali-Americana" published in 1829 so identified the animal. In 1838, Bonaparte, basing his description on Richardson's account of 1829, proposed the new name _richardsonii_. Richardson himself, the following year in the "Zoology of Beechey's Voyage," accepted Bonaparte's name and it has been applied to the animal in the central part of the northern timber-belt of North America ever since, except as authors used the name _Mustela erminea_ in the belief that _richardsonii_ was not distinct from _erminea_.

The north and south boundaries of the range assigned to _richardsonii_ varied according to the notions of the particular writer who was employing the name. Until Merriam in 1896 named _arctica_ as distinct, animals from the far north were generally included under the name _richardsonii_ along with populations to which the latter name now is applied. Because _richardsonii_ grades gradually into the smaller _cicognanii_ of more southern occurrence the boundary between the two has been set farther north by one writer and farther south by another, depending probably upon what the writer felt was the halfway point in size. This point of course depended upon the samples selected as typical of _richardsonii_ on the north and _cicognanii_ on the south. Because Bangs, in 1896, took as representative of _richardsonii_ the far northern and hence large-sized animals (now separated as _M. e. arctica_), his halfway point in size between them and the small _cicognanii_ of New England naturally fell farther north than it would have had he used as representative of _richardsonii_ specimens from places south of the range of _arctica_.