Chapter XII: Introduction (11)

Criddle and Criddle (1925:143, 146) say that weasels drinking at a bird trough "held their mouths very close to the water and as far as we could see, lapped the liquid up with rapid movements of the tongue. As a rule, after drinking, they would merely spring to the ground and vanish amid a bunch of scolding birds, but occasionally we have seen an animal slowly drag itself through the water and follow this performance by some rapid gambols, or a quick run, a method of drying which most of us have practiced in our youth." According to Hamilton's (1933:332) observations on captives, "Weasels are great drinkers, and while they take but little at a time, about 25 c.c. is drunk by a large animal during a day. . . ."

Reproduction

Philip L. Wright's several papers (1942A, 1942B, 1947, 1948A, and 1948B) reporting on his detailed studies of _Mustela frenata_ (subspecies _oribasus_ and _longicauda_) in captivity have yielded a large share of the precise information that we have concerning breeding and reproduction in this species. He has found that a single litter, of up to 9 young is born in the spring, usually in April. At three months of age the females "are full grown." The young males remain sexually immature during the first summer but the young females, as well as the females which are more than a year old, come into heat in the midsummer and are bred by the adult males. After a long period of quiescence lasting for several months, the embryos resulting from these matings become active in early spring and develop to full term in less than 27 days after they become implanted. The adult males are sexually active from April into August, when the testes are at maximal size and are conspicuous in the scrotum. A gradual regression takes place starting in August and extending into September. By October the testes may be fully regressed and the molt to white may start in this month. The white winter weasel, of either sex, is sexually inactive. The testes of the sexually active male in early spring and late summer are seven to eight times the size of the fully regressed testes. Females which had borne and suckled young were first found to be in oestrus 65 to 104 days after birth of the young. Lactation lasts for approximately 5 weeks. In 18 litters the length of the gestation period varied from 220 to 337 days with an average of 279 days. The female in heat has the vulva much swollen and she will remain in this condition for several weeks if not bred. Wright (1948A) describes the actual mating as beginning with a scuffle after which the male grabs the female by the scruff of the neck with his teeth and holds her until she becomes subdued when he clasps her lower abdomen with his front feet and arches his back over her posterior regions. The two animals remain locked in this position usually for two hours and sometimes for longer than three hours. If the animals are left together, copulation may take place again on the same day or upon succeeding days.

Hamilton (1933:316-321) writes of a freshly born _M. f. noveboracensis_ that it ". . . was pink and much wrinkled. The wetness . . . did not entirely obscure a few sparse, rather long, white hairs . . . over its back and head. It had the pronounced and extraordinarily long neck of the adult." At one day of age the average weight of six individuals in the litter was 3.1 grams, which is 3 per cent of the weight of the adult female and 1-1/2 per cent of the weight of an adult male. At two weeks of age "The silky white hair . . . obscures the general flesh color of the skin, evident a week earlier. The hair on the back of the head and neck, also over the shoulders, is slightly longer than that of the back . . ." but there is no crest or mane or pompadour at this or any other age such as characterizes the juvenal ermine. When 21 days old one young male "hurried from the nest chamber and commenced to eat some meat." At three and a half weeks "They are all eating small pieces of meat. . . . The canine teeth have made their appearance in both the upper and lower jaw, but just a hint of the incisors show. Some of the cheek teeth are through, as the meat appears to be thoroughly masticated by the little ones." On the 36th and 37th days the eyes opened. Sanderson (1949:415) found that a litter of seven young of _Mustela frenata longicauda_, from Manitoba, raised in captivity, "reached the peak of their growth" at approximately ten weeks of age.

Several nests have been found. In Manitoba, Sanderson (1949:412) excavated a burrow at the mouth of which he had trapped the adult female and in which he found eight young approximately five weeks old. The "burrow was about three inches in diameter, with two chambers at a depth of twelve inches. One of these was empty, the other contained the young. The two surface-openings were but two feet apart and the entire burrow was no more than three feet long. . . . The meager nest material consisted entirely of finely chopped grass. There was no mouse hair present, no accumulation of fecal material, and no storehouse containing food."

Charles O. Handley has written me that on January 25, 1929, on the Sinkola Plantation, Thomas County, Georgia, he investigated the living quarters of a family of five weasels, four of which had been shot five days before by a hunter. According to the hunter each of the four which had been killed was approximately two-thirds the size of one which escaped into a hole in the ground. Handley found that the weasels had been using as headquarters a burrow in the trunk of an old uprooted oak as well as a nearby gopher burrow. The burrow in the oak was approximately ten feet long and had been excavated in the rotten wood. In a distance of fifty feet along the gopher tunnel there were several used openings with pathways leading away from each. On February 6, Handley, with the help of a friend, trapped a large male weasel near this place.

Criddle and Criddle (1925:143) describe a female which, one winter, slept in a bag of feathers in a basement of a house occupied by one of the authors; another weasel in winter made its headquarters in a threshing machine. The nest of the latter "was somewhat roughly constructed and consisted of a convenient bunch of straw and chaff under the cylinder."

Harper (1927:303) in the Okefinokee Swamp of Georgia dislodged a weasel from the house of a wood rat and was told of a den found in the swamp "in the trunk of a hollow cypress tree" from which a mother weasel and three young "about the size of mice" were obtained. "The bed contained, I suppose, a bushel or more of rabbit hair, rat hair, and squirrel hair. It looked like it must have been used as a den for several years, although there was no stink that I could detect except the musk from the old Weasel." Another female and three young approximately half grown were found in a hollow pine log.

Between January 6 and April 12, 1940, on 640 acres of land, in Washtenaw County, Michigan, four weasels were studied and each weasel used only one den in this period (Quick, 1944:78). Criddle (1930:279) remarks that _M. f. longicauda_ at Aweme, Manitoba, often makes its temporary headquarters in the burrows of pocket gophers (_Thomomys_). A female and three young weasels were found by Shaw (1921:167) using a nest of a mountain beaver in the burrow of that animal. Green (1936), in May, in Gratiot County, Michigan, saw a weasel enter a hole under a decayed log and investigated finding four young weasels in a nest mostly of _Microtus_ fur.

In the early part (winter and spring) of 1939, at Ames, Iowa, Polderboer, Kuhn and Hendrickson (1941) studied four weasels living in four separate dens on 160 acres typical of Iowa farmland and excavated three of the dens. One den was in a weed patch in an old mole run. The nest chamber, approximately nine inches in diameter and six inches below the surface of the ground "was filled with grasses packed in a layer-like formation. In the center of this mass was a nest hollow lined with patches of mouse and shrew fur. Beneath this layer of fur and at the sides of the nest were skins, various bones, and skulls of partially eaten mice and shrews . . . scats [were in the nest]. . . . At intervals, layers of clean grass had been laid over the filth of the former bed, thus giving the nest a stratified appearance." A second den, of a large male, was in a field of sweet clover two feet high in the former burrow of a Franklin's ground squirrel. The nest cell, seven inches in diameter and nine inches below the surface of the ground, "was lined with grasses mixed with much rabbit and mouse fur. Some scats, and bones and fur of mice and shrews were matted together in layers at the bottom of the nest." When this den was abandoned the male weasel occupied, for a month, another burrow, 20 rods distant, of a Franklin ground squirrel, in the field of sweet clover. The nest cell measured 11 by nine inches and was 11 inches below the surface of the ground. "Two nest layers were present. The first, composed chiefly of coarse straw and grass, had apparently been occupied at some time by a spotted skunk. . . . On top of the skunk nest was the weasel nest composed of fine grasses, mouse fur, and skeletal remains of mice."

Relation of the Sexes to each other and to the young

Quick (1944:75) writes that on March 28, in Michigan, he found the tracks of a male and those of a smaller animal, supposedly a female, meeting. The two "then led along the fence for about 18 chains and both entered the den of the male. . . . Only the tracks of the smaller weasel left the den on the same date. Observation on April 12 showed that the large male still occupied the den." I am at a loss to explain this behavior since breeding would not be expected to occur in late March and since I suppose that the male and female do not live together except in the breeding season. Consequently, I wonder if the sign was wrongly read.

1. _M. f. noveboracensis_
2. _M. f. occisor_
3. _M. f. primulina_
4. _M. f. arthuri_
5. _M. f. olivacea_
6. _M. f. peninsulae_
7. _M. f. spadix_
8. _M. f. longicauda_
9. _M. f. oribasus_
10. _M. f. alleni_
11. _M. f. arizonensis_
12. _M. f. nevadensis_
13. _M. f. effera_
14. _M. f. washingtoni_
15. _M. f. saturata_
16. _M. f. altifrontalis_
17. _M. f. oregonensis_
18. _M. f. munda_
19. _M. f. xanthogenys_
20. _M. f. nigriauris_
21. _M. f. latirostra_
22. _M. f. pulchra_
23. _M. f. inyoensis_
24. _M. f. neomexicana_
25. _M. f. texensis_
26. _M. f. frenata_
27. _M. f. leucoparia_
28. _M. f. perotae_
29. _M. f. macrophonius_
30. _M. f. goldmani_
31. _M. f. tropicalis_
32. _M. f. perda_
33. _M. f. nicaraguae_
34. _M. f. costaricensis_
35. _M. f. panamensis_
36. _M. f. meridana_
37. _M. f. affinis_
38. _M. f. aureoventris_
39. _M. f. helleri_
40. _M. f. macrura_
41. _M. f. agilis_
42. _M. f. boliviensis_
43. _M. a. africana_
44. _M. a. stolzmanni_

Hamilton (1933:328), however, writes that _M. f. noveboracensis_ is to "be found in pairs when caring for the young. During mid-May, 1927, I several times saw a male of this species carrying food to a den of young ones." Green (1936), in May in Gratiot County, Michigan, remarks that while he was uncovering and examining a nest of four young weasels, two adults ran about excitedly and one removed a young weasel. In instances where several nearly full-grown young have been obtained from one den it has been my experience (Hall, 1946:191) that the only adult trapped there was the female; no adult male was found or in the one instance when found he was living alone in a den 200 yards away from the den of the female and her young. Data are too few to warrant a definite conclusion about the extent to which the male aids in rearing the young, but I have wondered if he might not do so when the young were less than half grown and then live alone when they were more than half grown.

=Mustela frenata noveboracensis= (Emmons)

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

_Putorius Noveboracensis_ Emmons, Quadrupeds of Massachusetts, p.
45, 1840.

_Mustela fusca_ DeKay, Zool. of New York, Pt. 1, Mammalia, p. 34,
1842.

_Putorius fuscus_ Audubon and Bachman, Journ. Acad. Nat. Sci.
Philadelphia, 8 (Pt. 2):288, 1842; Audubon and Bachman, Vivip.
quadrupeds of N. Amer., 3:234, pl. 148, 1853 (pl. 1848).

_Putorius noveboracensis_, DeKay, Zool. of New York, Pt. 1,
Mammalia, p. 34, 1842; Baird, Mamm. N. Amer., p. 166, 1858;
Merriam, N. Amer. Fauna, 11:16, pl. 4, figs. 1, 1a, 2, 2a, pl. 5,
figs. 3, 3a, text figs. 4-6, 30, June 30, 1896; Bangs, Proc.
Biol. Soc. Washington, 10:13, pl. 1, figs. 2, 2a, pl. 2, figs. 2,
2a, and pl. 3, figs. 3, 3a, February 25, 1896; Cory, Mamm.
Illinois and Wisconsin, p. 366, plates, 1912.

_Putorius erminea_, Audubon and Bachman, Vivip. quadrupeds of N.
Amer., 2:56, pl. 59, 1851.

_Putorius agilis_ Audubon and Bachman, Vivip. quadrupeds of N.
Amer., 3:184, pl. 140, 1853.

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

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

_Putorius noveboracensis notius_ Bangs, Proc. New England Zool.
Club, 1:53, June 9, 1899. Type from Weaverville, Buncombe County,
North Carolina.

_Mustela noveboracensis noveboracensis_, Miller, U. S. Nat. Mus.
Bull., 79:97, December 12, 1912; Soper, Journ. Mamm., 4:251,
November 1, 1923.

_Mustela cicognanii_, Henninger, Journ. Mamm., 2:239, November 29,
1921; Seton, Lives of game animals, 2:584, 1929 (part, Ohio);
Hamilton, Amer. Midland Nat., 14:290, July, 1933 (part, Ohio);
Lyon, Amer. Midland Nat., 17:109, January, 1936 (part, Ohio).

_Mustela noveboracensis_, Jackson, Journ. Mamm., 3:15, February 8,
1922.

_Mustela frenata noveboracensis_, Hall, Carnegie Instit. Washington
Publ. 473:104, November 20, 1936; Hall, Amer. Midland Nat.,
18:304, March, 1937.

_Type._--Williamstown, Berkshire County, Massachusetts. Type
specimen not known to be in existence.

_Range._--Altitudinally, sea level to highest parts of mountains
of eastern United States; Canadian Life-zone of Ontario and Quebec
southward through eastern United States in Canadian, Transition
and Upper Austral life-zones to and including upper edge of Lower
Austral Life-zone in the Carolinas and northern parts of Georgia,
Alabama, and Mississippi; westward from the Atlantic Coast to St.
Croix and Mississippi rivers. See figure 29 on page 221.

_Characters for ready recognition._--Differs: From _M. f.
olivacea_, in males, by width of tympanic bulla which is less than
rather than more than 8.5 mm., and in adult females by total
length which is less than rather than more than 345 mm. and by
mastoid breadth which is less than rather than more than distance
between articular faces of exoccipital condyle and glenoid fossa;
from _M. f. occisor_ by a number of average differences including
smaller size, relatively shorter tail and relatively narrower
skull (see measurements); from _M. f. spadix_ by least width of
color of underparts amounting to less than 41 per cent of greatest
width of color of upper parts, absence of color of underparts on
ankles and feet, adults with hind foot less than 50 in males and
40 in females, orbitonasal length less than 15.5 in males and 13.5
in females, length of tooth-rows less than 18.0 in males and 15.7
in females, mastoid breadth less than 25.5 in males and 22.0 in
females; from _M. f. primulina_ in males by interorbital breadth
averaging more than 24 per cent of basilar length, orbitonasal
length averaging more than 34 per cent of basilar length or 64 per
cent of mastoid breadth, tympanic bullae less inflated
anteromedially, than posteromedially, and in females by
orbitonasal length amounting to more than two-thirds of mastoid
breadth, by zygomatic breadth averaging less than 21, and by
anterolateral margin of tympanic bullae not projecting below
squamosal; from _M. f. arthuri_ in males, by zygomatic breadth
more than distance between anterior palatine foramen and anterior
margin of tympanic bulla and by convex dorsal outline of skull in
longitudinal axis.

_Description.--Size._--Male and Female:

=======================================================================
| Number | | |Per cent| |
LOCALITY | of | Total | Length | of | Length of |
| specimens | length | of tail | body- | hind foot |
| averaged | | | length | |
----------+------------+-----------+-----------+--------+-------------+
| 8 ad. [M] | 415 | 146 | 54% | 46.0 |
Massa- | | (390-432) | (127-159) | | (41.0-48.0) |
chusetts +------------+-----------+-----------+--------+-------------+
| 4 ad. [F] | 311 | 104 | 50% | 33.9 |
| | (298-321) | (95-114) | | (31.5-37.0) |
----------+------------+-----------+-----------+--------+-------------+
| 10 ad. [M] | 411 | 141 | 52% | 47.1 |
Liberty | | (379-438) | (124-155) | | (43.0-51.5) |
Hill, +------------+-----------+-----------+--------+-------------+
Conn. | 6 ad. and | 318 | 105 | 49% | 33.0 |
| sad. [F] | (303-338) | (80-123) | | (31.7-36.0) |
----------+------------+-----------+-----------+--------+-------------+
| 10 ad. [M] | 407 | 130 | 47% | 46.0 |
Beaver | | (372-431) | (113-143) | | (42.0-50.0) |
Dam, +------------+-----------+-----------+--------+-------------+
Wisc. | 4 ad. [F] | 326 | 99 | 43% | 35.6 |
| | (303-338) | (86-108) | | (34.6-38.0) |
----------+------------+-----------+-----------+--------+-------------+
| 10 ad. [M] | 371 | 130 | 54% | 45.0 |
Washtenaw | | (350-405) | (115-140) | | (40.0-50.0) |
Co., +------------+-----------+-----------+--------+-------------+
Mich. | 10 ad. [F] | 306 | 97 | 46% | 34.0 |
| | (290-335) | (90-120) | | (30.0-40.0) |
----------+------------+-----------+-----------+--------+-------------+

The length of the hind foot averages more than the basal length in
males whereas the reverse is true in females. The tail, relative
to the length of the body, is longer in males than in females. The
average differences in external measurements of the two sexes in
Massachusetts, are: total length, 104; length of tail, 42; length
of hind foot, 12.1. In Michigan, where the males are smaller,
corresponding differences are only, 65, 33, and 11. Weight of 19
adult males from New York (Hamilton, 1933:294), 225 (196-267)
grams and in 13 adult females, 102 (72-126) grams. Weights of 2
adults from Michigan are: [M] 258; [F] 101 grams.

_Externals._--Longest facial vibrissae black, brown, or white
(often all three colors in same specimen) and extending beyond
ear; carpal vibrissae same color as underparts and extending to
apical pad of fifth digit; hairiness of foot-soles as shown in
figure 19.

_Color._--Upper parts, in summer, Vandyke Brown or darker than
tone 4 of Burnt Umber of Oberthür and Dauthenay, pl. 304.
Sometimes approaching tone 2 of Warm Sepia of Oberthür and
Dauthenay, pl. 305. Underparts, in summer, ranging from white
through Napthalene Yellow (Peterboro, N. Y.), Pale Orange Yellow
(eastern Mass.), near Primuline Yellow (unusual specimen from
Leelanau Co., Mich.) to near (_c_) Deep Chrome (no. 19053, U. S.
Nat. Mus., Roan Mts., N. C). In winter, all white except tip of
tail, or upper parts near (12" 1) Rood's Brown and tone 2 of Raw
Umber of Oberthür and Dauthenay, pl. 301, with underparts white or
sometimes tinged with yellowish. Tip of tail at all times black.
Upper parts of uniform color except for occasional slight
darkening of nose. Color of underparts extends distally on
posterior sides of forelegs to foot and sometimes over upper sides
of toes and on medial sides of hind limbs only to knees. Least
width of color of underparts averaging, in a series of twenty-two
males, mostly in full winter pelage, from Liberty Hill,
Connecticut, 21 (11-40) per cent of greatest width of color of
underparts. In eleven females from the same place, corresponding
percentages are 20 (14-29). Black tip of tail in same series of
males, most of which are in full winter pelage, 70 (60-75) mm.
long; thus longer than hind foot and averaging 50 per cent of
length of tail-vertebrae.

_Skull and teeth._--Male (based on ten adults from Massachusetts):
See measurements and plates 16-18; weight, 3.6 (3.3-4.4) grams;
basilar length, 44.6 (43.3-46.0); zygomatic breadth less than
distance between condylar foramen and Ml or than between anterior
palatine foramen and anterior margin of tympanic bulla; mastoid
breadth less than postpalatal length; postorbital breadth more or
less than length of upper premolars and greater than width of
basioccipital measured from medial margin of one foramen lacerum
posterior to its opposite; interorbital breadth more or less
(usually more) than distance between foramen opticum and anterior
margin of tympanic bulla; breadth of rostrum less than length of
tympanic bulla; least width of palate less than length of P4;
anterior margin of tympanic bulla as far posterior to foramen
ovale as width of 3 to 6 upper incisors; height of tympanic bulla
more or less than distance from its anterior margin to foramen
ovale; length of tympanic bulla more than length of lower molar
and premolar tooth-row and longer or shorter than rostrum;
anterior margin of masseteric fossa behind or directly below
posterior fourth of m1.

Female (based on five adults from Mass.): See measurements and
plates 31-33; weight, 1.7 (1.2-2.1) grams; basilar length, 36.5
(35.2-38.1); zygomatic breadth less than distance between condylar
foramen and M1 or than between anterior palatine foramen and
anterior margin of tympanic bulla; postorbital breadth more or
less than length of upper premolars and more than width of
basioccipital measured from medial margin of one foramen lacerum
posterior to its opposite; least width of palate more or less
(usually less) than greatest length of P4; tympanic bulla as far
posterior to foramen ovale as width of 4 to 5-1/2 upper incisors;
height of tympanic bulla less than distance from its anterior
margin to foramen ovale; length of tympanic bulla more than length
of lower molar and premolar tooth-row and longer than rostrum.

The skull of the female averages 53 per cent lighter than that of
the average male.

Comparisons of the skull with those of _M. f. olivacea_, _M. f. spadix_, _M. f. primulina_, and _M. f. arthuri_, are made in the accounts of those subspecies. As compared with that of _M. f. occisor_ the skull of adult male _noveboracensis_, is of smaller average size with relatively (to basilar length of Hensel) lesser mastoid and zygomatic breadths. In addition to the zygomatic arches of _noveboracensis_ being less widely bowed outward they seem to be more rounded posteriorly. Comparisons of subadult females indicate that these differences exist in the females as well as in the adult males.

_Remarks._--The earliest of the post-Linnaean references to this weasel mostly were under the specific name _erminea_ in the belief that the American animal was the same as the larger of the two common species of weasel in the Old World. The name _noveboracensis_, now in use for this subspecies, was applied in 1840 and since that time the males usually have borne that name; the females, because they are smaller, were more frequently confused with some other species. Audubon and Bachman in 1853 even proposed the name _agilis_ for the female in the mistaken belief that it was a species distinct from the male. After 1896, when Bangs correctly classified the weasels of the eastern United States, the males have been correctly identified and the females, except by a few authors, likewise have been correctly named. Because many early American naturalists did their first collecting of mammals in the geographic range of _noveboracensis_, the person who examines labels of specimens of this subspecies can find data written in the hand of Spencer Fullerton Baird, Theodore Roosevelt, and other naturalists famous for their work as scientists or accomplishments otherwise. The material is more nearly adequate than is that of many other subspecies and the number of specimens is exceeded--and only slightly--by that of the subspecies _nevadensis_, which like _noveboracensis_ has a relatively large geographic range.

Intergradation with _Mustela frenata spadix_ is indicated by subadult males from western Wisconsin, namely, one from Gordon, three from Colfax and one from Meridean. Linear measurements of the teeth of these specimens are exactly intermediate between those of _spadix_ from Elk River, Minnesota, to the west, and _noveboracensis_ from, say, Beaver Dam, Wisconsin, to the east. The specimens from western Wisconsin show approach to spadix also in that the length of the tooth-rows and breadth of the rostrum are slightly greater than in _noveboracensis_ from farther east, say, Beaver Dam, Wisconsin.

Indeed, animals from as far east as Beaver Dam itself might be thought of as showing some approach to _spadix_. Although, along the eastern seaboard, the upper lips, with rare exceptions, are the same color as the underparts, farther west, in Michigan and Wisconsin, the lips more often than not are white. Animals from Beaver Dam have slightly shorter black tips on the tails, broader extent of the light color of the underparts and females average slightly larger than typical _noveboracensis_, say, those from Massachusetts. Each of these differences reflects characters found better developed in the _spadix-longicauda_ stock to the west.

Toward the southern part of its range where _noveboracensis_ meets _M. f. olivacea_ there is a marked increase in yellowness of the underparts. This coloration of the underparts, since it is not so well marked in the northern part of the range of _noveboracensis_, might be regarded as showing intergradation with _olivacea_ and _primulina_, each of which has far more intensely colored underparts than does _noveboracensis_. Excepting this increase of yellow on the underparts, however, there are few if any characters of _noveboracensis_ which undergo marked change as approach to the range of _olivacea_ is made. Indeed, the characters of _noveboracensis_ remain constant to within a relatively short distance of the geographic range of _olivacea_.

Notwithstanding the state of affairs described above, intergradation seems to take place. Three specimens referred to _noveboracensis_ but which at the same time are regarded as intergrades with _olivacea_ are as follows: No. 28.300, Charleston Museum, from five miles east of York, South Carolina, is an adult female with a badly crushed skull. In external measurements the specimen agrees with _noveboracensis_. The underparts, as regards color and width, are intermediate. The general proportions of the skull and tympanic bullae agree with those of _noveboracensis_ but the skull is larger than in any female of true _noveboracensis_ and approaches that of _olivacea_. The same can be said of a young female, no. 80, Ohio State Museum, from Roswell, Georgia.

Another female, no. 171559, U. S. Nat. Mus., from Lookout Mountain, 1500 ft., Fort Payne, Alabama, is barely subadult. The external measurements are nearer those of _olivacea_. The color and narrowness of the underparts are typical of _noveboracensis_. The proportions and especially size of the skull show approach to _olivacea_, though they are nearer to _noveboracensis_ when all features are taken into account. In the northern part of its range individuals of _noveboracensis_ attain larger size than farther south. This tendency reaches its extreme, in males at least, in _M. f. occisor_ of Maine. Specimens of _noveboracensis_ from the Adirondacks of New York average larger (see cranial measurements on page 418) than those from farther south, and thus approach _occisor_ in size as well as in geographic position. Also, occasional individuals which strongly show characters of _occisor_ are found even farther south than the Adirondacks of New York. This is true of no. 96518, U. S. Nat. Mus., [M] ad., from Lunenburg; Massachusetts. The animal has a large skull of relatively great width much as in _occisor_, although its external measurements, relative length of tail and long, terminal, black brush place it with _noveboracensis_ rather than with _occisor_. Of a pair of specimens from Ossipee, New Hampshire, the male, no. 77108, U. S. Nat. Mus., has a long (175 mm.) tail, and short (60 mm.) black pencil as in _occisor_, although otherwise it is referable to _noveboracensis_. Still another specimen, a subadult male, no. 4193, Mus. Comp. Zoöl., from Upton, Maine, has a longer (51 mm.) hind foot than _noveboracensis_ although it otherwise agrees with that subspecies. As remarked by Bangs (1899:55), other than fully adult specimens from the range of _occisor_ are "troublesome," and would not be selected as distinct from _noveboracensis_ if placed in a series of that subspecies, say, from New York State. In view of the facts that several specimens from intermediate localities combine the characters of _noveboracensis_ and _occisor_, that _noveboracensis_ in the northern part of its range averages larger than it does farther south and thus approaches _occisor_ in size, and that occasional large specimens resembling _occisor_ in several, but not all, features sometimes crop up in the northern part of the range of _noveboracensis_, it appears that _noveboracensis_ and _occisor_ intergrade. Therefore they are treated as two subspecies of the single species, _Mustela frenata_.

Intergradation with _M. f. primulina_ has been commented on in the discussion of that subspecies. Female, no. 159980, U. S. Nat. Mus., from Golconda, Illinois, has many characters of _primulina_ but two young males from there agree better with _noveboracensis_.

Examination of 283 adult and subadult skulls for malformation of the frontal sinuses revealed only ten that were not obviously malformed. Two were from New York, one from Massachusetts, one from Pennsylvania, and six from the 52 specimens from Michigan and Wisconsin. In addition, skulls of many young and even juveniles were malformed.

_Specimens examined._--Total number, 555, arranged alphabetically
by states and provinces and, unless otherwise noted, from north to
south by counties in each state. Except as otherwise noted
specimens are in the United States National Museum.

=Alabama.= _DeKalb County_: Fort Payne, 1.

=Connecticut.= _Litchfield County_: Riverton, 1[5]; Gaylordsville,
1. _Hartford County_: East Hartford, 4 (3[5]); Glastonbury, 2[5];
South Glastonbury, 4[5]. _Windham County_: Plainfield, 2 (1[14]).
_Fairfield County_: Greenwich, 2[2]. _New London County_: Liberty
Hill, 35 (33[75], 2[7]).

=District of Columbia.= Washington, 3; near Washington, 1; Eastern
Branch, 1; Congress Heights, 1; Benning, 1; no definite locality,
1.

=Georgia.= _Towns County_: Young Harris, 1. _Cherokee County_:
Canton, 1. _Cobb County_: Roswell, 1[81].

=Indiana.= _St. Joseph County_: Notre Dame, 2[99]. _Porter
County_: Hebron, 1. _Miami County_: Denver, 5 (4[75], 1[4]).
_Wells County_: Bluffton, 1. _Howard County_: Russiaville, 1. _Jay
County_: Salamonia, 1[2]. _Boone County_, 1[2]. _Knox County_:
Bicknell, 3.

=Illinois.= _Lake County_: Camp Logan, 3[60]; Fort Sheridan,
1[60]. _Cook County_: W Northfield, 2; Flossmoor, 1[60]; no
locality more definite than county, 1. _Du Page County_:
Bloomingdale Spg., 1[60]. _Carroll County_: Savanna, 1[87].
_McLean County_: Normal, 1[7]. _Champaign County_: Harwood
Township, 1[7]. _Pike County_?: Milton Spring, 1[60]. _Pope
County_: Golconda, 3.

=Kentucky.= _Woodford County_: Midway, 1. _Hancock County_:
Hawesville, 1.

=Maine.= _Oxford County_: Upton, 1[75]; Bethel, 1[74].

=Maryland.= _Howard County_: Long Corner, 1; Hanover, 1.
_Montgomery County_: Gaithersburg, 1; Garret Park, 1; Chevy Chase,
1; Bethesda, 1. _Prince Georges County_: Laurel, 18; Plummer
Island, 3; Oxon Hill, 1. _Talbot County_: Easton, 1. _Dorchester
County_: Cambridge, 5[40].

=Massachusetts.= _Middlesex County_: Wilmington, 6; Burlington, 6;
Lexington, 1[75]; Wayland, 2[75]. _Berkshire County_: New
Marlboro, 1[5]. _Worcester County_: Lunenburg, 2; Lancaster,
1[75]; Princeton, 2[75]. _Norfolk County_: So. Weymouth, 1[75].
_Plymouth County_: Wareham, 5[75].

=Michigan.= _Marquette County_: Michigamme, 1. _Charlevoix
County_: Thumb Lake, 1[76]; 1/2 mi. N Thumb Lake, 1[76]. _Leelanau
County_: Leland, 3[76]; Duck Lake, 2 mi. S Leland, 1[76]; Lost
Pond, 8-1/2 mi. S Leland, 1[76]. _Osceola County_: Le Roy, 2[76].
_Huron County_: Rush Lake, 1[76]. _Saginaw County_: East Saginaw,
1. _Oakland County_: Royal Oak, 4[76]; South Lyon, 1[76].
_Livingston County_: Portage Lake, 1[76]. _Washtenaw County_:
Portage Lake, 6[76]; Waterloo, 2[14]; Lima, 1[76]; Ann Arbor,
11[76]; 3 mi. E Ann Arbor, 1[76]; 2 mi. SE Ann Arbor, 1[76]; 2 mi.
S Ann Arbor, 1[76]; 3 mi. S Ann Arbor, 1[76]; Dixboro, 1[76];
Pittsfield, 3 (2[76]); Saline, 1[76]; near Saline, 2[76]; 1 mi. S
Saline, 2[76]; York, 2[76]; Manchester, 2[76]. _Lenawee County_:
Morenci, 1[76]. _Cass County_: Marcellus Township, 1[76]. _Berrien
County_: Harbert, 1[76]; Warren Wood Preserve, 1[76]; Warren
Woods, 1[76].

=New Hampshire.= _Grafton County_: Franconia, 1[2]. _Carroll
County_: South Chatham, 4 (3[5]); Ossipee, 2; Intervale, 1[5].
_Merrimack County_: Webster, 2[75].

=New Jersey.= _Morris County_: Morristown, 1. _Essex County_: West
Orange, 1[2]. _Mercer County_: Princeton, 1[1]. _Ocean County_:
Point Pleasant, 1[2]. _Camden County_: Haddonfield, 1[1].
_Cumberland County_: Millville, 2[74].

=New York.= _St. Lawrence County_: Ogdensburg, 1[74]. _Clinton
County_: Rouses Point, 1[80]. _County_?: Adirondacks, 12. _Essex
County_: Elizabethtown, 1; Schroon Lake, 1; no locality more
definite than county, 1. _Lewis? County_: Locust Grove, 4; Lyons
Falls, 1. _Warren County_: Lake George, 6; Caldwell, 1. _Hamilton
County_: Beaver Brook, 1/2 mi. above mouth Indian Lake, 1[80].
_Oswego County_: Scriba, 2[74]; Palermo, 1[74]. _Monroe County_:
Penfield, 3. _Madison County_: Peterboro, 6 (2[75]). _Schoharie
County_: Schoharie, 1[2]. _Rensselaer County_: East Shodack,
1[80]. _Tompkins County_: Taughannock Falls, 2[58]; Ithaca, 4
(3[58]); Glenside, Ithaca, 1[58]; 6 mi. Creek, Ithaca, 1[58].
_Green County_: Lanesville, 1[2]. _Orange County_: Poplopen's
Pond, 1[2]; Highland Falls, 1[2]. _Putnam County_, 1[19].
_Westchester County_: Sing Sing, 4; Armonk, 1[2]; Hastings, 3
(2[2], 1[19]). _Nassau County_: Flushing Meadows, 1[2]; Flushing,
1[58]; near Flushing, 1[2]; Oyster Bay, 2. _Long Island_: Cold
Spring Harbor, 1; Bridgehampton, 1[2]. _County_ in question:
Severance, 3; Lake Grove (Long Island?), 1.

=North Carolina= (east to west by counties). _Wake County_:
Raleigh, 4 (1[2], 1[75], 2[76]). _Mitchell County_: Magnetic City,
foot of Roan Mountain, 6; Roan Mt., 1; Roan Mt., 6000 ft., 3.
_Buncombe County_?: Valley of Black Mts., 1[2]. _Madison County_,
2[11].

=Ohio.= _Trumbull County_: Warren, 1[93]. _Seneca County_: Tiffin,
1[81]. _Summit County_: Ira, 2[81]. _Crawford County_: Galion,
1[81]. _Ashland County_: Loudonville, 1[76]. _Auglaize County_:
New Bremen, 3[81]. _Franklin County_: 3 mi. N Columbus, 1[81];
Minerva Park, Columbus, 5[81]. _Fairfield County_: Sec. 32,
Pleasant Twp., 1[81]; Lancaster, 1[81]. _Clinton County_:
Reesville, 1; 1/2 mi. S and 1/2 mi. W Wilmington, 2[74]. _Pike
County_: Waverly, 1[81].

=Ontario.= _Sudbury District_: Metagama, 2[86]. _Carleton County_:
Ottawa, 2[77]. _Muskoka County_: Lake of Bays, 1; Bracebridge, 1.
_Haliburton County_: Gooderham, 1[60]. _Simcoe County_: Orillia, 4
(2[2], 2[60].) _Prince Edward County_: Bloomfield, 1[77]. _York
County_: Toronto, 1[2]. _Waterloo County_: Branchton, 3[60];
Preston, 2[77]; no locality save county, 1[60]. _Welland County_:
Ridgway, 1[14]. _Elgin County_: St. Thomas, 1[77]. _Essex County_:
Kingsville, 1[77]; Point Pelee, 1[77].

=Pennsylvania= (east to west by counties). _Crawford County_:
Pymatuning Swamp, 3-1/2 mi. W Linesville, 1[9]; Meadville, 2[9].
_Beaver County_: Beaver, 1[9]; Raccoon Creek, 1[9]. _Butler
County_: Mars, 1[9]; Leasuresville, 4[9]. _Allegheny County_:
Allegheny, 1. _Warren County_: Bear Lake, 2[9]. _Westmoreland
County_: Kingston, 1[9]; Laughlinstown, 2[9]. _Somerset County_:
Confluence, 1[9]; Tub Mill Run, 2 mi. N Springs, 1[9]. _Jefferson
County_: Siegel, 1[9]. _Clearfield? County_: Penfield, 1[9].
_Cambria County_: Cresson, 1[9]. _Fulton County_: Well's Tannery,
1[9]. _Clinton County_: near Round Island, 2[1]. _Cumberland
County_: Carlisle, 1. _Snyder County_: 5 mi. S Selinsgrove, 1.
_Northumberland County_: Pottsgrove, 1. _Union County_:
Mifflinburg, 1. _Sullivan County_: Lopez, 7 (4[1], 3[74]).
_Chester County_: Westtown, 1[1]; Valley Forge, 1[1]; W Bradford
Township, 1[1]; no locality more definite than county, 3.
_Philadelphia County_: Holmsburg, 2[1]. _Bucks County_: 1[1].
_Pike County_: Milford, 1.

=Rhode Island.= _Providence County_: Chepachet, 1. _Washington
County_: Lake Warden, 2.

=Quebec.= _Megantic County_: Black Lake 1[77]. _County_ in
question: Meach Lake, 1[77].

=South Carolina.= _York County_: 5 mi. E York, 1[11]. _Laurens
County_: Laurens, 1[39].

=Tennessee.= _Campbell County_: Highcliff, 1. _Carter? County_:
Roan Mts., 1[2]. _Hamilton County_: Walden Ridge, near Soddy, 3.

=Vermont.= _Windsor County_: Hartland, 1[2].

=Virginia.= _Shenandoah County_: Toms Brook, 1. _Arlington
County_: Arlington, 1; Ballston, 1; Alexandria, 1. _Fairfax
County_: Falls Church, 3; Mt. Vernon, 2; no locality more
definite than county, 1. _Prince William County_: Occoquan, 1.
_Essex County_: Montague, 1. _Prince George County_, 1. _Norfolk
County_: Wallaceton, 1. _Grayson County_: Mt Rogers, 3. _County_
in question: Dismal Swamp, 1; Massanutten Mt., 1.

=West Virginia.= _Hardy County_, 1. _Pendleton County_: radius of
2 mi. Smoke Hole, 1[74]. _Greenbriar County_: White Sulphur,
2[60].

=Wisconsin.= _Douglas County_: Gordon, 1[104]. _Vilas County_:
Mamie Lake, 4. _Dunn County_: Colfax, 4[104]; Meridean, 1[104].
_Door County_: state game farm, 17[104]; no locality more definite
than county, 1[104]. _Dodge County_: Rolling Prairie, 1[50];
Beaver Dam, 52[50]. _Dane County_: Wingra Lake, 1[104]. _Waukesha
County_: Pewaukee, 2[104]. _Racine County_: Waterford Township,
2[104]. _Rock County_: Milton, 1[104]; Bowers Lake, 1[104].
_Walworth County_: Lane's Mill, 8 mi. N Elkhorn, 7 (1[104],
6[54]); Delavan, 7.

=Mustela frenata occisor= (Bangs)

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

_Putorius occisor_ Bangs, Proc. New England Zool. Club, 1:54, June
9, 1899.

_Mustela occisor_, Miller, U. S. Nat. Mus. Bull., 79:98, December
31, 1912.

_Mustela frenata occisor_, Hall, Carnegie Instit. Washington Publ.
473:104, November 20, 1936.

_Type._--Male, adult, skull and skin; no. 9102, coll. of E. A. and
O. Bangs in Mus. Comp. Zoöl.; Bucksport, Hancock County, Maine;
January 15, 1899; obtained by Alvah G. Door but measured and sexed
by O. Bangs.

The skin is well made and in good condition. It is in full, white
winter-dress with black-tipped tail. The skull has the posterior
half of the left zygomatic arch broken away; otherwise the skull
is unbroken and complete. Left I3 and right P3 are missing. The
teeth otherwise all are present and entire.

_Range._--Maine; possibly north locally to south side of St.
Lawrence River in Quebec and possibly occurring in western New
Brunswick. Zonal range Canadian and probably Transition. See
figure 29 on page 221.

_Characters for ready recognition._--Differs from _M. f.
noveboracensis_ by a number of average differences including
larger size, relatively longer tail and relatively wider skull
(see p. 225, and measurements on pp. 418, 419).

_Description._--_Size._--Male: Five adults yield average and
extreme measurements as follows: Total length, 443 (430-465);
length of tail, 163 (154-175); length of hind foot, 50 (47-54).
Tail averages 58 per cent as long as head and body. Length of hind
foot averages more than basal length.

Female: Measurements of two subadult female topotypes are as
follows: Total length, 346, 318; length of tail, 116, 110; length
of hind foot, 39, 35.5.

Tail amounts to 50 per cent and 54 per cent of body-length
respectively. Length of hind foot more or less than (about equal
to) basal length.

The average differences in external measurements of the two sexes
are: Total length, 111; length of tail, 50; length of hind foot,
12.5.

_Externals._--As described in _Mustela frenata noveboracensis_.

_Color._--As described in _Mustela frenata noveboracensis_ except
that black tail-tip in series of 10 males in full winter pelage 60
(45-80) mm. long; thus averaging 39 per cent of length of tail
vertebrae.

_Skull and teeth._--Male (based on 3 adults): See measurements and
plates 16-18. As described in _Mustela frenata noveboracensis_
except that: Weight, 4.2 (4.1-4.3) grams; basilar length, 45.7
(44.9-46.9); zygomatic breadth more or less than (about equal to)
distance between anterior palatine foramen and anterior margin of
tympanic bulla; least width of palate rarely less than length of
P4; anterior margin of masseteric fossa behind or directly below
posterior half of m2.

Female (based on 2 subadults): See measurements and plates 31-33.
As described in _Mustela frenata noveboracensis_ except that:
Weight, 2.0 (1.9-2.1) grams; basilar length, 37.3, 38.2.

Comparison of the skull with that of _M. f. noveboracensis_ is
made in the account of that subspecies.

_Remarks._--Excepting a specimen in the Academy of Natural Sciences of Philadelphia, obtained in 1893, and two in the Boston Society of Natural History, obtained in 1925, I have seen no material of this subspecies in addition to that examined by Bangs at the time he prepared the original description in 1899.

Anderson (1945:56, 57) records a specimen, Canadian National Museum Catalogue Number 18426, from Kamouraska County, Quebec, as of this subspecies and thinks that _occisor_ occurs north of Maine "locally to south side of lower St. Lawrence River in Quebec; probably also in western New Brunswick."

So far as the available material of occisor permits one to judge, it is distinguished from _noveboracensis_ by a combination of characters no one of which invariably can be relied upon as diagnostic. Employing adult males, average differences indicate that _M. f. occisor_ is larger in each of the external and cranial measurements; tail relatively longer; black tip of tail relatively shorter; mastoid and zygomatic breadth relatively greater and zygomatic arches more nearly square posteriorly.

Considering the large number of specimens of _noveboracensis_ which are available in comparison with the few of _occisor_ it is not surprising that some _noveboracensis_ should be found which exceed in size those of _occisor_. This is the case as regards the basilar length of a very old male, no. 96518, U. S. Nat. Mus., from Lunenburg, Massachusetts. Also, the skull is actually broader than any of those of _occisor_. However, this specimen is much older than any _occisor_ examined. In a female, no. 4260, Mus. Comp. Zoöl., from Liberty Hill, Connecticut, the skull is longer (but narrower) than in either of the two available females of _occisor_.

The average differences pointed out above which characterize this extreme northern population of _noveboracensis_-like weasel in comparison with true _noveboracensis_ without much question are geographic variations. Whether or not these variations are of a degree sufficient to warrant nomenclatural recognition is debatable. With equally scanty material from other regions I have not named variations seemingly as great as those shown by _occisor_. The paucity of material of _occisor_ is a handicap in making a decision in this instance.

Each of the adult and subadult specimens, except the one from Perry, shows malformation resulting from the infestation of the frontal sinuses with parasites.

_Specimens examined._--Total number, 18, listed by counties from
west to east and unless otherwise indicated in the Museum of
Comparative Zoölogy.

=Maine.= _Oxford County_: South Andover, 2 (Boston Soc. Nat.
Hist.); Umbagog Lake, 1. _Franklin County_: Seven Pd. Township, 1.
_Piscataquis County_: Grenville, [= Greenville?], 1. _Hancock
County_: Bucksport, 10. _Washington County_: 3rd Mopang Lake, 1
(Acad. Nat. Sci. Phila.); Perry, 1 (Boston Soc. Nat. Hist.).
_County_ in question: Moosehead Lake, 1.

=Mustela frenata primulina= Jackson

Long-tailed Weasel

Plates 16, 17, 18, 31, 32 and 33

_Mustela primulina_ Jackson, Proc. Biol. Soc. Washington, 26:123,
May 21, 1913.

_Putorius noveboracensis_, Baird, Mamm. N. Amer., p. 166, 1858
(part).

_Mustela longicauda longicauda_, Dice, Journ. Mamm., 4:108, May 9,
1923.

_Mustela longicauda primulina_, Linsdale, Journ. Mamm., 9:141, May
9, 1928.

_Mustela frenata primulina_, Hall, Carnegie Instit. Washington
Publ. 473:104, November 20, 1936.

_Mustela frenata_, Leopold and Hall, Journ. Mamm., 26:143, July 19,
1945.

_Type._--Male?, young, skull and skin; no. 168006, U. S. Nat.
Mus., Biol. Surv. Coll.; 5 miles northeast of Avilla, Jasper
County, Missouri; May 11, 1905; obtained by Hartley H. T. Jackson;
original no. 7869X.

The skin lacks the distal part of the tail--the part which bears
the black tip. Otherwise the skin is complete and well preserved.
The teeth of the permanent dentition all are present and entire.
The lower jaws are complete and unbroken. The skull is broken
transversely through the interorbital region, transversely through
the braincase and longitudinally through the basioccipital. Both
zygomatic arches are gone. The type is judged to be a male rather
than a female as stated by the original describer, Jackson
(1913:123), whose measurements of hind foot, interorbital
constriction, maxillary tooth-row, and mandibular tooth-row agree
with those of males and are larger than those of any female seen
of this subspecies.

_Range._--Upper and Lower Austral life-zones west of the
Mississippi River in Missouri and Arkansas, the southeastern half
of Iowa, eastern half of Kansas and Oklahoma, northern Louisiana
and northeastern Texas. Southern and southwestern limits of range
undetermined. See figure 29 on page 221.

_Characters for ready recognition._--Differs from _M. f.
noveboracensis_ in males by interorbital breadth averaging less
than 24 per cent of basilar length, orbitonasal length averaging
less than 34 per cent of basilar length or 64 per cent of mastoid
breadth, tympanic bullae as much inflated anteromedially as
posteromedially, and in females by orbitonasal length amounting to
less than two-thirds of mastoid breadth, by zygomatic breadth
averaging more than 21 mm., and by anterolateral margin of
tympanic bulla projecting below squamosal; from _M. f. spadix_ by
least width of color of under parts amounting to less than 40 per
cent of greatest width of color of upper parts, by absence of
color of underparts on hind leg below knee, and by smaller size
(hind foot less than 50 in males and 40 in females; orbitonasal
length less than 15.5 in males and 13.5 in females; length of
tooth-rows less than 18 in males and 15.7 in females; mastoid
breadth less than 25.5 in males and 22 in females); from _M. f.
longicauda_ by Brussels Brown rather than near (_h_) Clay Color of
upper parts, least width of underparts less than 40 per cent of
greatest width of color of upper parts, absence of color of
underparts on hind leg below knee, zygomatic breadth less than
28.8 in males and 24.1 in females; from _M. f. neomexicana_ by
Brussels Brown rather than Buckthorn Brown color of upper parts,
in absence of white frontal spot and broad white bands on sides of
head, in anterolaterally rounded, rather than "square," tympanic
bullae and in zygomatic breadth of less than 30 in males and 24 in
females; from _M. f. frenata_ and _M. f. texensis_ by absence of
white facial markings and smaller size (basilar length of adult
males less than 47, tail-length less than 155 in males, and hind
foot less than 40 in females); from _M. f. arthuri_ by less evenly
spreading zygomatic arches (see pls. 16, 17 and 18), greater
inflation of the tympanic bullae anteromedially and more nearly
straight (less convex) dorsal outline of skull.

_Description._--_Size._--Male: Eighteen adults and subadults from
Douglas County, Kansas, yield average and extreme measurements as
follows: Total length, 397 (371-440); length of tail, 133
(120-147); length of hind foot, 43 (40-47). Tail averages 50 per
cent as long as head and body. Length of hind foot averages less
than basal length. Corresponding measurements, originally taken in
inches and fractions thereof, of 9 adults and subadults from Boone
County, Arkansas, are as follows: 413 (384-438); 138 (127-155); 41
(38-44).

Female: Six adults and subadults from Douglas County, Kansas,
yield average and extreme measurements as follows: Total length,
339 (317-355); length of tail, 107 (95-115); length of hind foot,
35 (34-37). Tail averages 46 per cent of length of head and body.
Length of hind foot less than basal length. Corresponding
measurements, originally taken in inches and fractions thereof, of
5 adults and subadults from Boone County, Arkansas, are as
follows: 355 (332-397); 113 (101-127); 33 (29-38).

The average differences in external measurements of the two sexes,
in Douglas County, Kansas, are: Total length, 58; length of tail,
26; length of hind foot, 8. An adult male from Boone Co., Iowa,
weighed 293 grams.

_Externals._--Longest facial vibrissae black or dark brown (often
both colors in same specimen) and extending beyond ear; carpal
vibrissae colored either like underparts or upper parts and
extending to apical pad of fifth digit; hairiness of foot-soles as
shown in figure 20.

_Color._--Upper parts, in summer, Brussels Brown to near (14 _n_)
Brussels Brown, or tones 2 to 4 of Raw Umber of Oberthür and
Dauthenay, pl. 301. Chin and rarely upper lips white. Remainder of
underparts Picric Yellow to Primuline Yellow. In winter, color
essentially the same except for smoke-gray effect in upper parts
and more whitish in underparts. Tip of tail at all times black.
Upper parts of uniform color except for occasional darkening of
nose and mid-dorsal region. Color of underparts extends distally
on posterior sides of forelegs onto antipalmar faces of toes, on
medial sides of hind legs only to a point between knee and ankle.
Least width of color of underparts averaging, in a series of 21
males from Lawrence, Kansas, 23 (9-35) per cent of greatest width
of color of upper parts. Black tip of tail in same series, most of
which are in full winter pelage, 52 (40-70) mm. long; thus longer
than hind foot and averaging 39 per cent of length of
tail-vertebrae.

_Skull and teeth._--Male (based on ten adults from Douglas County,
Kansas): See measurements and plates 16-18; weight, 3.7 (3.3-4.2)
grams; basilar length, 44.8 (43.8-46.0); zygomatic breadth more or
less (less in 80 per cent) than distance between condylar foramen
and M1 or than between anterior palatine foramen and anterior end
of tympanic bulla (less in 70 per cent); mastoid breadth more or
less (less in 80 per cent) than postpalatal length; postorbital
breadth less than length of upper premolars and, except in one
specimen, more than width of basioccipital measured from medial
margin of one foramen lacerum posterior to its opposite;
interorbital breadth more or less (less in 70 per cent) than
distance between foramen opticum and anterior margin of tympanic
bulla; breadth of rostrum less than length of tympanic bulla;
least width of palate less than outside length of P4 (except in
one specimen); anterior margin of tympanic bulla as far posterior
to foramen ovale as width of 2-1/2 to 5 upper incisors; height of
tympanic bulla more (except in one specimen) than distance from
its anterior margin to foramen ovale; length of tympanic bulla
more than length of lower molar and premolar tooth-row and longer
(except in one specimen) than rostrum; anterior margin of
masseteric fossa behind or just below posterior eighth of m1.

Female (based on 5 adults and subadults from Douglas County,
Kansas): See measurements and plates 31-33; weight, 2.2 (2.0-2.4)
grams; basilar length, 38.9 (37.6-40.7); zygomatic breadth less
than distance between condylar foramen and M1 or than between
anterior palatine foramen and anterior margin of tympanic bulla;
postorbital breadth less than length of upper premolars and except
in one specimen, more than width of basioccipital measured from
medial margin of one foramen lacerum posterior to its opposite;
least width of palate less than greatest length of P4; tympanic
bulla as far posterior to foramen ovale as width of 3 to 5 upper
incisors; height of tympanic bulla more or less than distance from
its anterior margin to foramen ovale; length of tympanic bulla
more than length of lower molar and premolar tooth-row and longer
than rostrum.

The skull of the female averages 41 per cent lighter than that of
the male.

Compared with the skull of _M. f. noveboracensis_ from Massachusetts, that of the male of _primulina_, in dorsal view, is seen to be shorter anteriorly to the postorbital processes and to have a more marked postorbital constriction. In lateral view the dorsal outline of the skull of _primulina_ is less concave in the postorbital region. In ventral view the skull of _primulina_ is seen to be wider across the mastoid processes and zygomatic arches but the most pronounced difference is in the tympanic bullae. In _noveboracensis_ each bulla is scooped out on the anterior part of the medial face and appears to be narrower anteriorly than posteriorly whereas in _primulina_ the anterior part of the medial face is not scooped out but is moderately inflated and the bulla appears to be of uniform breadth anteriorly and posteriorly. By actual measurement the breadth of the bulla averages 59 per cent of its length in _primulina_ but only 50 per cent in _noveboracensis_. Other respects in which the skull of the male of _primulina_ differs from that of _noveboracensis_ are as follows: Linear measurements of teeth more; relative to the basilar length, the length of the tooth-rows averages more, whereas the interorbital breadth and orbitonasal length are less.

When skulls of females are compared, each of the differences mentioned above is found to apply, except that the degree of difference is in some parts greater, for example, in the tympanic bullae. In _primulina_, the bulla is in general like that of the male _noveboracensis_, whereas in the female _noveboracensis_ it is less inflated, especially anteromedially, shorter, relatively narrower, and in ventral view projects little or none below the squamosal floor of the braincase. The breadth of the bulla averages 51 per cent of its length in _primulina_ but only 47 per cent in _noveboracensis_. The bullae project below the basioccipital on the average, for a distance of 2.9 millimeters in female _primulina_ and only 2.3 millimeters in female _noveboracensis_. In _primulina_ the temporal ridges are well developed and fuse to form a low sagittal crest, but in _noveboracensis_ the ridges are absent. Also, in _primulina_ the mastoid processes project farther laterally beyond the braincase. The skull of female _noveboracensis_ is much lighter than that of _primulina_. Average weights of the two are 1.7 and 2.2 grams. The skulls of females of _primulina_ and _noveboracensis_ differ more than do the skulls of males.

Compared with the skull of _spadix_, that of the male, and the female, of _primulina_ averages smaller in every part measured. Expressed in percentages of the basilar length, the two depth measurements of the skulls are not significantly different, but, excluding the measurements of the bullae and teeth, the other cranial measurements are less. The main difference in relative proportions is in the tympanic bullae which average only a half millimeter shorter in males of _primulina_ and one and one-tenth millimeters shorter in females. The bullae are, therefore, relative to the basilar length, longer in _primulina_. The skull of _primulina_, then, differs from that of _spadix_ mainly in smaller size and relatively longer tympanic bullae, especially in males.