Chapter XXI: Introduction (20)

_Range._--Pacific coastal regions of Ecuador and Colombia;
Subtropical and Tropical life-zones. See figure 29 on page 221.

_Characters for ready recognition._--Differs from _Mustela
africana stolzmanni_ by absence of median, longitudinal, abdominal
stripe of same color as upper parts, by presence of p2 and by two
rather than one root on P2; from _Mustela frenata macrura_ by
Reddish Black, tone 4, plate 344 rather than Chocolate, tone 3,
pl. 343 (of Oberthür and Dauthenay), or slightly darker color of
upper parts; from _M. f. affinis_ and _M. f. meridana_ by darker
color (tone 4 rather than tone 2, Reddish Black of Ober. and
Dauth.) of upper parts and larger size of teeth (M1 with length
more than 2.4 and breadth more than 4.7; P4 with outside length
more than 5.9; length of m1 more than 6.2).

_Description._--Unless otherwise stated, information concerning
this subspecies is derived from the one referred specimen
available, a young male, no. 34677, Amer. Mus. Nat. Hist.

_Size._--Male: Total length, 470; length of tail, 160; length of
hind foot, 50. Tail 51 per cent as long as head and body.

Female: Not known.

_Externals._--Longest facial vibrissae black and reaching beyond
ear. Carpal vibrissae reaching to or beyond apical pad of fifth
digit; hairiness of foot soles slightly less than shown in figure
20.

_Color._--Sides and top of head and neck posteriorly to shoulders
black; white facial markings represented by only five white hairs
anterior to right ear, one anterior to left ear and three far back
on forehead; dark areas at angles of mouth confluent with color of
upper parts; tip of tail black; remainder of upper parts near
(_n_) Bay or Reddish Black, tone 4 of Oberthür and Dauthenay, pl.
344; chin whitish; remainder of underparts Warm Buff, deep orange
in juvenile, type specimen, according to Gray (1864, pl. 8); color
of underparts extending distally on posterior sides of forelegs to
wrists but not reaching foot soles and on hind legs to or slightly
below knees. Least width of color of underparts equal to 15 per
cent of greatest width of color of upper parts. Black tip of tail
equal to 27 per cent of length of tail-vertebrae.

In color, no. 34677 is, to me as it was to Allen (1916:101),
indistinguishable from the darkest specimens (nos. 178970 and
10112) of _M. f. panamensis_. Therefore, _M. f. aureoventris_ is
one of the two darkest subspecies of weasels.

_Skull and teeth._--Male: See measurements and plates 27-29;
weight, 4.3 grams; basilar length, 45.8; zygomatic breadth
approximately equal to distance between condylar foramen and M1
and to distance between anterior palatine foramen and anterior
margin of tympanic bulla; mastoid breadth less than postpalatal
length; postorbital breadth more 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 greater than distance between foramen opticum
and anterior margin of tympanic bulla; breadth of rostrum less (at
least in young specimen) than length of tympanic bulla; least
width of palate seldom if ever greater than length of P4; anterior
margin of tympanic bulla as far posterior to foramen ovale as
width of three (including I3) upper incisors; height of tympanic
bulla not greater than distance from its anterior margin to
foramen ovale; length of tympanic bulla more than length of lower
molar and premolar tooth-row and shorter than orbitonasal length;
anterior margin of masseteric fossa below anterior half of m2.

Skulls of males of _M. f. aureoventris_, and _Mustela frenata
macrura_ from the vicinity of Quito so closely resemble one
another as not to be distinguished with the material now
available, although the teeth of _aureoventris_ are larger.
Comparisons of the skulls of males with those of _M. f. meridana_
and _affinis_, which are readily distinguishable from those of
_aureoventris_, have been made in the accounts of those
subspecies.

Female: Skull of adult unknown.

_Remarks._--This subspecies of the Tropical Life-zone, or at least the Subtropical Life-zone, of Ecuador, in certain cranial characters resembles _Mustela frenata macrura_ of the Temperate Life-zone. The two differ markedly in color. Nevertheless, a large number of the specimens collected in Ecuador are intermediate in color as well as in zonal distribution.

The type specimen is young or a juvenile. The measurements of no. 34677 from Gualea indicate an animal similar in size to _M. f. affinis_. Gray (1864:55) states that the type specimen measures "Length of body and head 6 inches, of tail 4-1/2 inches." The plate (pl. 8) accompanying Gray's original description (_loc. cit._) is marked one-half natural size and represents the animal as having a head and body length of eight and one-half inches. One year later Gray (1865:115) gives the measurements of this species as "Length of body and head 12, tail 8 inches." Since he had at this time another specimen, larger than the type specimen (which specimen later, probably, became the type of _Mustela affinis_ Gray), the larger measurements probably were taken from it.

Geographically, and as regards cranial characters, _Mustela frenata aureoventris_ is most closely related to _M. f. affinis_ and to the northern section of _M. f. macrura_, but in color to _M. f. panamensis_. _M. f. aureoventris_ and _M. f. panamensis_ are the two darkest-colored subspecies and each occurs in a region of extremely heavy rainfall. There is a skin only, no. 32620, Amer. Mus. Nat. Hist., from Munchique, obtained on June 1, 1911, which is appreciably darker than specimens of _M. f. affinis_ in corresponding pelage and is intermediate between _M. f. affinis_ and _M. f. aureoventris_ in color as it is geographically. The specimen measures 495, 202, 52.

The name _Mustela aureoventris_ Gray has been regarded by most authors as preoccupied by _Mustela auriventer_ Hodgson (1841:909). However, the writer is not of this opinion and agrees with Thomas (1920:224) that "The name _aureoventris_ is not invalidated by the _auriventer_ of Hodgson, as, apart from 'one-letterist' differences, its first half comes from the adjective _aureus_, while Hodgson's name is based on the substantive _aurum_, so that not only the spellings but the derivations are different." The spelling of Gray's name should be _aureoventris_ for this is the spelling in the original description which in pagination precedes the colored plate of the animal that is labeled _Mustela aureoventris_. _Putorius brasiliensis_ var. _aequatorialis_ Coues (1877:142) is the only name known to the writer that has been proposed as a substitute for _Mustela aureoventris_ Gray.

Thomas (1920:224) treats _Mustela macrura_ Taczanowski as a synonym of _Mustela aureoventris_ Gray. Allen (1916:101) also treats the two names as applying to the same kind of weasel but regards _aureoventris_ as preoccupied and therefore uses the name _macrura_. Taczanowski's original description (1874:311) and plate of _Mustela macrura_ indicate an animal that is lighter colored than _M. f. affinis_. Gray's original description (1864:55) and plate of _aureoventris_ indicate an animal that is darker colored than _M. f. affinis_. Indeed Gray (1865:115) in speaking of the type of _aureoventris_ as compared with an adult from New Granada [= Colombia] that probably later became the type specimen of _Mustela affinis_, states: "The young from Quito is much darker than the adult;. . . ." Comparison of the plates accompanying the original descriptions of _aureoventris_ and _macrura_ well illustrate the difference stated in the written descriptions. My examination of the type specimens of _M. macrura_ and _M. f. aureoventris_ shows them to have been fairly accurately portrayed in the plates accompanying the original descriptions. Accordingly the two names are used for the two kinds of animals which appear, however, to be only subspecifically distinct.

Comparison of Gray's plate (1864, pl. 8) with the available specimens from South America indicates that the name _aureoventris_ is based on an individual that is lighter colored than no. 34677 Amer. Mus. Nat. Hist., from Gualea, Ecuador, but on one which resembles no. 34677 more than it does the lighter-colored specimens from the Temperate Zone of Ecuador and northern Perú. Because Quito, Ecuador, is in the Temperate Life-zone and because the available specimens from this zone in Ecuador and northern Perú are distinctly lighter colored than Gray's plate representing the type of _aureoventris_ shows this specimen to be, it is judged to have come from an altitude lower than that of Quito (9350 feet, according to Chapman, 1926:717); probably it came from the Subtropical Life-zone of Ecuador. Indeed Gray (1864:55) did not say that the specimen was collected or obtained at Quito but that it was ". . . received from Quito. . . ." Chapman (1926:717) has pointed out that Quito, since 1846 has been the distributing point for bird skins which specimens ". . . come from the vicinity of the city, from the 'Napo' region on the Amazonian slopes of the Andes, and from Nanegal, Gualea, and other localities on the Pacific side rarely below the Subtropical Zone." It is also pointed out that only some of the specimens are labeled with their approximate place of capture and that even then these localities cannot be accepted as definite; they indicate mainly whether the specimen is from the eastern or western side of the Andes.

The above mentioned considerations and information gained by study of the specimens cause me to think that the type is an intergrade tending toward the lighter-colored _Mustela f. macrura_ of the Temperate Zone although sufficiently dark to be referred to the dark subspecies represented by no. 34677 Amer. Mus. Nat. Hist., from Gualea, Ecuador.

The skull of no. 34677 shows no infestation of the frontal sinuses by parasites.

_Specimens examined._--Total number, 3, as follows:

=Ecuador=: Gualea, 1, Amer. Mus. Nat. Hist.

=Colombia=: 8325 ft., Munchique, 1, Amer. Mus. Nat. Hist. In the
British Museum of Natural History, the type, (1).

=Mustela frenata helleri= Hall

Long-tailed Weasel

Plates 27, 28 and 29

_Mustela frenata helleri_ Hall, Proc. Biol. Soc. Washington,
48:143, August 22, 1935; Hall, Carnegie Instit. Washington Publ.
473:110, November 20, 1936; Hall, Physis, 16:175, 1939.

_Type._--Male, adult, skull and skin; no. 24133, Field Mus. Nat.
Hist.; 3000 feet, Hacienda San Antonio, Río Chinchao, Perú; August
22, 1922. Obtained by Edmund Heller. Original no. 6589.

The skull (plates 27-29) is complete and unbroken. The teeth all
are present, entire and but slightly worn. The skin is well made,
unfaded, and in good condition.

_Range._--Three thousand feet (type locality) to 6700 feet (Ambo),
Tropical and Subtropical life-zones of eastern Perú. See figure 29
on page 221.

_Characters for ready recognition._--Differs from _Mustela
africana stolzmanni_ by absence of median, longitudinal, abdominal
stripe of same color as upper parts, presence of p2 and two roots
rather than one root on P2; from _Mustela frenata macrura_ by
darker color (Carbon Brown, tone 3, pl. 342 rather than Chocolate,
tone 3, pl. 343, Oberthür and Dauthenay) of upper parts.

_Description._--_Size._--Male: Measurements of the type specimen
and topotype, no. 24132, are, respectively, as follows: Total
length, 382, 418; length of tail, 152, 164; length of hind foot,
52, 48. Tail 66 and 65 per cent as long as head and body. Hind
foot more than basal length.

Female: Measurements of two referred females, no. 24134 from Ambo
and no. 24136 from Huanuco, are, respectively, as follows: Total
length, 328 and 303; length of tail, 118 and 103; length of hind
foot, 39 and 38.5. Tail 56 and 51 per cent as long as head and
body. Hind foot shorter than basal length.

The average differences in external measurements of the two sexes
are: Total length, 85; length of tail, 49; length of hind foot,
11.

_Externals._--Longest facial vibrissae black and extending beyond
ear; carpal vibrissae same color as upper parts and extending to
apical pad of fifth digit; hairiness of foot-soles as shown in
figure 20.

_Color._--Rarely a few white hairs anterior to each ear; posterior
fifth of each upper lip white; top of head, posteriorly to
slightly behind ears, black, grading into color of upper parts of
body; dark spots at angles of mouth absent; tip of tail black;
remainder of upper parts near (_n_) Argus Brown and Carbon Brown,
tone 3 (pl. 342, Oberthür and Dauthenay); chin whitish; remainder
of underparts Warm Buff; color of underparts extends distally on
posterior sides of forelegs to wrists but not reaching foot-soles
and on hind legs to slightly below knees. Least width of color of
underparts 24 per cent of greatest width of color of upper parts
in each of two males and 19 to 30 per cent in three females. Black
tip of tail longer than hind foot and averaging 40 (39-42) per
cent of length of tail-vertebrae.

_Skull and teeth._--Male (based on type specimen and adult no.
24132): See measurements and plates 27-29. As described in
_Mustela frenata macrura_ except that: Weight, 4.5 (4.2 and 4.8);
basilar length, 44.6 (44.0-45.3); zygomatic breadth more than
distance between condylar foramen and M1 or than between anterior
palatine foramen and anterior margin of tympanic bulla; breadth of
rostrum more or less than (approximately equal to) length of
tympanic bulla; height of tympanic bulla less than distance from
its anterior margin to foramen ovale; length of tympanic bulla
less than length of rostrum; anterior margin of masseteric fossa
posterior to m2 by length of that tooth.

Female (based on nos. 24134 to 24136): See measurements. As
described in _Mustela frenata macrura_ except that: Weight, 1.7
(1.5-1.9) grams; basilar length, 36.5 (35.3-38.1); zygomatic
breadth less than distance between anterior palatine foramen and
anterior margin of tympanic bulla; least width of palate more or
less than (approximately equal to) outside length of P4; length of
tympanic bulla less than length of rostrum.

The skull of the female averages 62 per cent lighter than that of
the male.

The skull of the male is generally large and heavy as are the teeth. Comparison with _macrura_ is made in the account of that subspecies. From males of _affinis_ those of _helleri_ differ in: skull shorter; breadth of rostrum and interorbital breadth actually and relatively greater.

_Remarks._--The five specimens examined of this subspecies were taken by Edmund Heller for the Field Museum of Natural History in 1922 and 1923. It is to honor his contributions to mammalogy that the subspecies is named _helleri_. No. 24135 is the specimen carried as a pet for some time by Mr. and Mrs. Heller and of which Mrs. Heller (1924:481) has given an account.

This subspecies is insufficiently known, especially as to geographic range; probably it occupies a considerable range in the Tropical Life-zone along the eastern base of the Andes. The three females, two from Ambo and one from Huanuco, come from a much higher altitude than do the two males and the climate is said to be arid at Ambo and Huanuco. The skulls of the females are 62 per cent lighter and correspondingly smaller in measurements, than those of males. This difference is more than that found in any other South American weasel and it may be that the females are of a subspecies other than _helleri_.

The type specimen has a broad skull with major proportions strikingly like those of _Mustela stolzmanni_. Possibly the similar climatic conditions under which the two live have left their impress in similar fashion in this part of each of the two species. The teeth, tympanic bullae, and certain other parts of the skull are, however, so differently proportioned as to show that the skulls represent two species. The referred male has a much longer skull than the type specimen and the relative proportions of breadth and depth of the two skulls differ widely. Judging from large series of weasels examined from localities outside the range of _M. f. helleri_, the two skulls probably represent almost the maximum of individual variation occurring in one subspecies.

The dark color is as might be expected since _helleri_ inhabits the humid Tropical Zone.

None of the five skulls shows signs of having had the frontal sinuses infested by parasites.

_Specimens examined._--Total number, 5, all in the Field Museum of
Natural History.

=Perú=: 3500 ft., Hacienda Buena Vista, Río Chinchao, 1; 3000 ft.,
Hacienda San Antonio, Río Chinchao, 1; Huanuco, 1; Ambo, 2.

=Mustela frenata agilis= Tschudi

Long-tailed Weasel

Plates 27, 28, 29, 39 and 40

_Mustela agilis_ Tschudi, Fauna Peruana, p. 110, 1844; Gray, Proc.
Zoöl. Soc. London, 1865:113, 1865; Taczanowski, Proc. Zoöl. Soc.
London, 1874:311, 1874; Taczanowski, Proc. Zoöl. Soc. London,
1881:648, 1881; Allen, Bull. Amer. Mus. Nat. Hist., 35:104; April
28, 1916; Thomas, Proc. U. S. Nat. Mus., 58-224, 1920.

_Mustela macrura_, Allen, Bull. Amer. Mus. Nat. Hist., 35:103,
April 28, 1916.

_Mustela frenata agilis_, Hall, Carnegie Instit. Washington Publ.
473:110, November 20, 1936; Hall, Physis, 16:176, 1939.

_Type._--No type specimen, or type locality more restricted than
cold, barren highlands of the Cordillera [referring to Perú]
designated.

_Range._--High, barren Cordillera of Perú (see Tschudi, orig.
descr.); as here restricted, Temperate Life-zone and higher in
western Andes and intermountain valleys of Perú. See figure 29 on
page 221.

_Characters for ready recognition._--Differs from _Mustela frenata
macrura_ by lighter color (Chocolate, tone 2 rather than 3, pl.
343, Oberthür and Dauthenay) of upper parts; length of upper
tooth-rows, in females, less than 13; inside length of P4 more
than 4.6; from _M. f. aureoventris_ by smaller teeth (maximum size
just given for _agilis_); from _M. f. boliviensis_ by lighter
color, upper parts being Chocolate, tone 2, pl. 343, rather than
tone 4 or darker of Carbon Brown, pl. 342 (Oberthür and
Dauthenay).

_Description._--_Size._--Male: The stuffed skin of an adult, from
Lima, measures: Total length, 460; length of tail, 125; length of
hind foot, 45.7. A skin alone from Huarochirí has a body, as now
stuffed, 277 mm. long. The tail is missing and the bones of the
hind feet have been removed.

Female: The mounted specimen, no. 565, Mus. Polonais d'Hist. Nat.,
yields measurements, taken by me, as follows: Total length, 250;
length of tail, 75; length of hind foot, 32.5. The female, no.
21147, from Macate, measures, 300, 102, 34.

_Externals._--Longest facial vibrissae, either dark-or
light-colored and extending beyond ear; carpal vibrissae either
dark-or light-colored and extending to apical pad of fifth digit;
hairiness of foot soles as shown in figure 20.

_Color._--Tschudi's description of the color is, in substance, as
follows: Head, back and tail reddish gray; base of hair gray,
followed by broader grayish-yellow ring and then reddish-brown
tip; nose simply dark brown or upper lips edged with white;
throat, breast, belly and higher parts of inner sides of
extremities whitish gray, at times wholly gray, bases of hairs
always gray; feet darker than body, almost chestnut brown; tail
darker on tip than at base; ears externally dark brown, internally
whitish.

No. 565 possibly somewhat faded from exposure to light, has all
the upper parts near (14´ _j_) Ochraceous-Tawny or Cinnamon, and
tone 4 of Oberthür and Dauthenay, plate 323; posterior half of
each upper lip white; no other white facial markings present; dark
spot at each angle of mouth (one spot confluent with color of
upper parts); tip of tail probably black (tip missing); underparts
white, belly probably originally with slight tinge of yellow or
allied color; color of underparts extending distally on forelegs
to feet and onto upper sides of toes and on hind legs to just
above heels. Least width of color of underparts equal to about
one-fourth of greatest width of color of upper parts.

No. 21147, subadult, from Macate, has a white band confluent with
the underparts extending anterodorsally anterior to each ear and
the posterior third of each upper lip white. Top of head near
(_n_) Mars Brown, and Carbon Brown, tone 3 (pl. 342, Ober. and
Dauth.); tip of tail black; remainder of upper parts near (16"
_j_) Tawny-Olive, and Chocolate (tone 2, of pl. 343 of Ober. and
Dauth.) or Raw Umber (tone 3 of pl. 301 of Ober. and Dauth.);
anterior half of underparts, including posterior sides of forelegs
and antipalmar faces of forefeet, white; remainder of underparts
tinged with Warm Buff and extended on posterior legs almost to
ankles.

No. 8.1.10.1., male adult, from Lima, is also light colored, and
as described in no. 21147, except that left side of head has a
white spot rather than bar; posterior eighth of each upper lip
white; white frontonasal spot present, 11 x 11 mm.; antipalmar
faces of forefeet spotted with brown color of upper parts; color
of underparts extending distally on hind legs along medial side of
foot to point halfway between heel and tip of inner toe.

No. 13257 from Huarochirí in color and color pattern closely
resembles no. 21147. It differs from no. 21147 in slightly lighter
color of upper parts, entirely white underparts, less extension of
color of underparts onto forefeet, few white hairs instead of
white band in front of each ear; color of underparts more
restricted.

In each of the four specimens, the least width of the underparts,
expressed as a percentage of the upper parts, is as follows: no.
13257, 11 per cent; no. 21147, 29 per cent; no. 565, 31 per cent;
no. 8.1.10.1., nineteen per cent.

_Skull and teeth._--Male (based on no. 8.1.10.1.): See
measurements and plates 27-29. As described in _Mustela frenata
macrura_ except that: Weight 4.1 grams; basilar length, 42.5;
zygomatic breadth more than distance between anterior palatine
foramen and anterior margin of tympanic bulla; mastoid breadth
less than postpalatal length; tympanic bullae shorter than
rostrum.

Female (based on no. 21147): See measurements and plates 39 and
40. As described in _Mustela frenata macrura_ except that: Weight
(no. 21147, subadult), 1.5 grams; basilar length, 35.2; least
width of palate less than outside length of P4; tympanic bulla as
far posterior to foramen ovale as combined width of five upper
incisors; no. 565 answers to the same description but differs from
no. 21147 in greater basilar length and larger tympanic bullae
which are slightly more projected, at their anterior margins, from
the braincase.

To judge from the skull of the female from Macate and the skull of the male from Lima, the skull and teeth of _agilis_ are smaller than in any other South American subspecies of _Mustela frenata_, except _M. f. boliviensis_.

_Remarks._--Tschudi almost certainly used the name _Mustela agilis_ in a composite sense. His statement (see quoted matter below) about the marked variation in color of this species, as represented by the skins carried by the Indian women as purses, indicates that the forms here designated as _Mustela macrura_, _M. helleri_ and possibly others additional to the one here called _agilis_ were included by him under the name _Mustela agilis_. Taczanowski took account of _Mustela agilis_ when he described other species from Perú. Allen (1916:104) and Thomas (1920:224) were not convinced that _Mustela agilis_ and _Mustela macrura_ were distinct species or subspecies.

Search on August 28, 1937, in the Musée d'Histoire Naturelle, at Neuchatel, Switzerland, by Mr. Théodore Delachaux, assistant there, and the writer, revealed no trace of weasels from Tschudi's collection, although some other specimens of mammals that he figured in the "Fauna Peruana" are preserved in that Museum. Not only were the collections of specimens examined but the new catalogue and old catalogue of mammals were vainly searched for mention of weasels deposited by Tschudi. Later, at the British Museum of Natural History, on page 105 of a personal notebook, of the late Mr. Oldfield Thomas, record was found of his fruitless search for the same specimens of _Mustela_ in May, 1902, at Neuchatel.

Although Tschudi certainly used the name _Mustela agilis_ in a composite sense, as subspecies are at present understood, his description most nearly applies to the light-colored animals from western Perú--the lightest colored of any South American weasels seen. They are of approximately the same color as North American subspecies inhabiting semiarid regions, for example _Mustela frenata longicauda_ of the Great Plains.

Another, but in my opinion less weighty, justification for applying Tschudi's name _agilis_ to these light-colored weasels of western Perú is that by one line of reasoning, Taczanowski in naming _macrura_ (_jelskii_ is a synonym of it) from farther eastward in Perú, and that Hall in naming _helleri_ from still farther eastward, and _boliviensis_ to the southeastward, geographically restricted the application of the name _agilis_. Hall's action did this because he recognized geographic variation and employed the subspecies concept. Taczanowski, however, proposed his name _macrura_ for a kind of animal which he indicated was specifically (as opposed to subspecifically) distinct from _agilis_ and his account (1881:649) of _jelskii_ indicates that he thought _Mustela agilis_ Tschudi might occur in the same place as the animals which he named as new kinds. Thus, we can not credit Taczanowski with _intent_ to restrict the name _agilis_ geographically, even though later authors may choose to rule that his naming of _macrura_ in effect did so restrict the application of _Mustela agilis_ Tschudi.

The equivalents in millimeters given by Allen (1916:104) for Tschudi's measurements of 9 to 10 inches entire length, and tails of 4 inches to 4 inches and 4 lines, apparently are based on the London scale in use today. If Tschudi employed the Rhine scale also of eight lines to the inch, but one which has the foot longer by an amount of 20 millimeters, or the Leipzig scale in which the foot is 22 millimeters shorter than the London foot, the measurements recorded by Tschudi differ in one direction or the other from those computed by Allen. However, knowledge of which scale Tschudi employed would not help much, if any, in more precise application of the name _agilis_ because he does not indicate whether his measurements are of male or female animals; animals of the two sexes of the same subspecies differ more in external measurements than animals of the same sex of different subspecies of Peruvian weasels.

Specimen no. 565, in the Polish Museum of Natural History, without definite locality, is provisionally referred to this subspecies. The specimen is intermediate in several respects between the female from Macate and the one of _macrura_ from Cutervo.

Tschudi (1844:111-112) has given the following account:
"_Lebensweise und geographische Verbreitung_. Das peruanische
Wiesel lebt auf den kalten, öden Hochebenen der Cordillera an
sonnigen Steinhaufen und Felsen gewöhnlich in Gesellschaft von
8-12 Stücken. Diese Thierchen sind so ausserordentlich behende und
scheu, dass bei dem leisesten Geräusche die ganze Schaar mit
Blitzesschnelle verschwindet. Es ist uns auch nie gelungen, eines
derselben zu erlegen. Die Indianer aber verstehen es, dieselben
lebendig einzufangen und zu zähmen. Ein sehr zahmes sahen wir bei
einer uns befreundeten Dame in Tarma; gegen alle Fremden biss es
mit Wuth und liess sich nicht anfassen, während es sich von seiner
Herrin Alles gefallen liess; sie öffnete ihm den Mund und steckte
ihm den Finger hinein, ohne dass es eine böse Miene dazu machte,
während es bei der geringsten Bewegung, die wir machten, es zu
ergreifen, grimmig auf uns lossprang. Wenn es eingeschüchtert
wurde, versteckte es sich in den Busen seiner Gebieterin und kroch
ihr bald nachher zum Aermel heraus. An den Wänden und Meublen
kletterte es mit grosser Behendigkeit und schlüpfte durch so
kleine Ritzen und Löcher, dass wir fast an der Möglichkeit dieses
Hindurchdringens gezweifelt haben würden, wenn wir es nicht selbst
mit angesehen hätten. Wenn es unartig war, wurde es mit einer
Schnur an seinem kleinen Halsbande festgebunden; dadurch vermehrte
sich sein Zorn, so dass es zuweilen gegen die Dame auffuhr.
Mehrmals verschwand es während 8-10 Tagen und kam dann plötzlich
wieder zum Vorschein. Seine Nahrung bestand in Gemüse und Fleisch,
besonders aber liebte es Zuckerbrod in Milch aufgeweicht; einmal
machte es sich an einen Kanarienvogel, den es auch tödtete. Es
erhielt seine Strafe und verschwand dann für immer. Die Indianer
sollen dieses Wiesel zum Fange der Viscacha abrichten (davon
weiter unten). Sie nennen es Comadreja, auch Ardilla. ([footnote]
Ardilla ist spanisch und heisst Eichhörnchen. Mit diesem Namen
werden sehr verschiedene Thiere bezeichnet; ausser dem Sc.
variabilis und der Galictis agilis auch noch mehrere Nager und
einige Didelphysarten.) Die Indianerinnen verfertigen sich aus dem
kleinen Felle Geldbeutel. Des Sonntags trifft man unter den vielen
tausend Punaindianerinnen die nach den grossen Dörfern der Sierra
kommen, um ihre Einkäufe zu machen, kaum ein halbes Dutzend, die
nicht solche Börsen mit sich führten, und dann kann man auch die
verschiedensten Farbennuancen, die bei dieser Species vorkommen,
beobachten."

None of the three skulls referred to this subspecies shows infestation of the frontal sinuses by parasites.

_Specimens examined._--Total number, 4.

=Perú=: Macate, 1 (Field Mus. Nat. Hist.); Huarochirí, 1 (Mus.
Comp. Zool.); Lima, 1 (British Mus. Nat. Hist.); no locality more
definite than Perú, 1 (Mus. Polonais d'Hist. Nat.).

=Mustela frenata macrura= Taczanowski

Long-tailed Weasel

Plates 1, 27, 28, 29, 30, 37, 38, 39 and 40

_Mustela macrura_ Taczanowski, Proc. Zoöl. Soc. London, 1874:311,
pl. 48, May 19, 1874; _ibid_., 1881:647, May 17, 1881; _ibid_.,
835, November 15, 1881; Lönnberg, Arkiv för Zool., 8 (no. 1):21,
1913 (?); Hollister, Proc. Biol. Soc. Washington, 28:143, July
10, 1914; Allen, Bull. Amer. Mus. Nat. Hist., 35:101, April 28,
1916; Lönnberg, Arkiv för Zool., 14 (no. 4):11, 1921.

_Putorius (Gale) braziliensis frenatus_, Coues, Fur-bearing
animals, p. 142, 1877.

_Mustela jelskii_ Taczanowski, Proc. Zoöl. Soc. London, 1881:647,
May 17, 1881.

_Mustela affinis_, Lönnberg, Arkiv för Zool., 8 (no. 1):21, July
12, 1913.

_Mustela aureoventris_, Thomas, Proc. U. S. Nat. Mus., 58:224,
1920.

_Mustela frenata macrura_, Hall, Carnegie Instit. Washington Publ.
473:110, November 20, 1936; Hall, Physis, 16:176, 1939.

_Type._--Male, adult, mounted skin, with skull separate; no. 561,
Mus. Polonais d'Hist. Nat. (Warsaw, Poland); Lake Junín, central
Perú; 1873; obtained by M. Jelski.

The skull (plates 27-29, 30), mounted with the skin but removed by
me for study, lacks the right jugal, the basisphenoid, the
basioccipital and parts of each exoccipital bearing the
exoccipital condyles. The right tympanic bulla, although detached
from the skull, is preserved separately. The teeth all are present
and entire. The skin is fairly-well mounted, in a good state of
preservation, and shows no fading due to exposure to light.

_Range._--Altitudinally, 3200 (Guainche) to at least 12000 feet
(Pichincha); Upper Subtropical and Temperate life-zones of central
Perú and Ecuador north from the states of Apurimac and Cuzco,
Perú, to San Antonio, northern Ecuador. See figure 29 on page 221.

_Characters for ready recognition._--Differs from _Mustela
africana stolzmanni_ by absence of median, longitudinal, abdominal
stripe of same color as upper parts; presence of p2 and two roots
rather than one root on P2; from _Mustela frenata helleri_, _M. f.
affinis_ and _M. f. aureoventris_ by lighter color of upper parts
which are Chocolate tone 3, pl. 343, Oberthür and Dauthenay,
whereas, with reference to the same color standard, the colors
are: in _helleri_, Carbon Brown, tone 3, pl. 342; in _affinis_,
Reddish Black, tone 2, pl. 344; in _aureoventris_, Reddish Black,
tone 4, pl. 344; from _M. f. agilis_ by darker color (Chocolate,
tone 3 rather than 2, pl. 343, Oberthür and Dauthenay) of upper
parts, length of upper tooth-rows, in females, more than 13,
inside length of P4 more than 4.6; from _M. f. boliviensis_ by
lighter color of upper parts which are as above rather than tone 4
of Carbon Brown, pl. 342 of Oberthür and Dauthenay, and larger
size (in males, hind foot more than 45 and m1 more than 5.6).

_Description._--_Size._--Male (measurements as recorded by
Taczanowski in the original description, for two specimens, type
and topotype, with correction of the length of tail of his
"female" [= male]): Total length, 420, 415; length of tail, 150,
145; length of hind foot, 51, 51. An adult from Yana Mayo, Río
Tarma, was measured by Hendee as 394, 134. Hind foot relaxed
measures, 47. Tail 55 per cent as long as head and body. Length
of hind foot more than basal length.

Female (based on measurements given by Taczanowski (1881:647) of
no. 564): Total length, 323; length of tail, 120; length of hind
foot, 37. Tail 59 per cent as long as head and body. Length of
hind foot approximately equal to basal length.

Differences in external measurements of the two sexes are: Total
length, 87; length of tail, 23; length of hind foot, 13.

_Externals._--Longest facial vibrissae extending beyond ear;
carpal vibrissae color of either upper parts or underparts;
hairiness of foot-soles as shown in figure 20.

_Color._--(Based on specimens from Cutervo and south thereof).
Rarely few white hairs between eyes and in front of ears; top of
head posteriorly to slightly behind eyes, near (_n_)
Chestnut-Brown (Ridgway) and Carbon Brown, tone 2 or darker (pl.
342, Oberthür and Dauthenay); posterior half of upper lip rarely
white; dark spots at angles of mouth absent; tip of tail black;
remainder of upper parts near (_l_) Russet (Ridgway) and
Chocolate, tone 3 (pl. 343, Ober. and Dauth.); underparts white or
whitish on medial sides of forelegs, otherwise cream color with
tinge of Ochraceous-Buff; color of underparts extended distally on
posterior sides of forelegs to just below elbow (in type specimen)
or onto forefeet (in specimen from Yana Mayo) and on medial sides
of hind legs to points between knees and ankles. Least width of
color of underparts averages (in six skins) 17 (14-21) per cent of
greatest width of color of upper parts. Black tip of tail longer
than hind foot and averaging 36 (32-49) per cent of length of
tail-vertebrae.

_Skull and teeth._--Male (based on type specimen and no. 562): See
measurements and plates 27-30; weight, not known; basilar length,
43.2 (40.8 and 45.5); zygomatic breadth more or less than distance
between condylar foramen and M1 and more than that between
anterior palatine foramen and anterior margin of tympanic bulla;
mastoid breadth more or less than postpalatal length; postorbital
breadth more 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 than
distance between foramen opticum and anterior margin of tympanic
bulla; breadth of rostrum less than length of tympanic bulla;
least width of palate more than inside length of P4; anterior
margin of tympanic bulla as far posterior to foramen ovale as
width of 4 (including I3) upper incisors; height of tympanic bulla
not more 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 below or behind m2.

Female (based on no. 564, from Cutervo, Perú, type specimen of
_Mustela jelskii_ Taczanowski): See measurements and plates 37-40;
weight, not known; basilar length, 38±; zygomatic breadth less
than distance between condylar foramen and Ml and not greater than
that between anterior palatine foramen and anterior margin of
tympanic bulla; postorbital breadth more than alveolar length of
upper premolars and (probably) more than width of basioccipital
measured from medial margin of one foramen lacerum posterior to
its opposite; least width of palate more than inside length of P4;
tympanic bulla as far posterior to foramen ovale as width of at
least 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 or shorter than rostrum.

As compared with that of _helleri_, the skull of the male of _macrura_ from Junín southward has a lesser mastoid breadth, notably smaller teeth, and a flatter skull which averages lighter throughout. The skulls of females available indicate that the skull and teeth are larger than in _agilis_.

_Remarks._--Seven years after Taczanowski named this subspecies, he applied the name _jelskii_ to a female taken farther north than the original examples of _macrura_. As indicated in synonymy, various other names have been applied to animals included by the present author in this subspecies.

_Mustela frenata macrura_ intergrades with _M. f. affinis_ as shown by practically all the referred specimens from north of Junín. As one proceeds northward the color of the weasels becomes progressively darker and the teeth become larger until the conditions found in _affinis_ are met with near the northern border of Ecuador. From the material available it appears that the light-colored upper parts found in _macrura_ characterize weasels of, at least, the Temperate Zone, from Marcapata, Perú, to near Quito, Ecuador. West of the range of _macrura_ there exists the still lighter-colored subspecies, _M. f. agilis_. Immediately adjacent on the north, east, and south, darker-colored weasels occur. So far as color is concerned, the geographic range of the subspecies _M. f. macrura_ is not difficult to define. However, the small size of the teeth characterizes only that part of this light-colored subspecies from Junín southward including the subspecies _boliviensis_ at the southern extremity of the range of the species. From Cutervo northward the light-colored weasels of the Temperate Zone have teeth similar in size to those of the darker, more northern _affinis_. To designate the slightly larger-toothed, light-colored animals from Ecuador as a subspecies distinct from _affinis_ and _macrura_ is one solution but at present it seems best to refer all of these light-colored animals to _macrura_.

The type specimen and topotype no. 562 differ more in the amount of inflation of the tympanic bullae than adult males of comparable ages from a given locality usually do. In other respects, the differences between the two skulls are not greater than those ordinarily found in specimens from the same locality. No. 562 has the tympanic bullae greatly, relative to the other South American weasels, inflated posteriorly. Otherwise, the bullae agree with those of the type specimen.

Specimens from southwestern Ecuador, average large, and include the largest specimens of the species _Mustela frenata_ seen from South America. A subadult male, no. 61406, in the American Museum of Natural History, is the largest. Its external measurements are 482, 191, 56. The basilar length of the skull is 48.2 and the zygomatic breadth is 30.3. Although not so large as this specimen, the corresponding measurements of specimens from Alamor, El Chiral, and even from as far away as Sigsig also are distinctly large.

The skull of the female from Ollantaytambo and that of the male from Marcapata have teeth equally as small as do the specimens from Lake Junín.

The skin alone, no. 194328, from Ollantaytambo has the color of the underparts extended over the entire upper sides of the forefeet. The male from Marcapata has less of this color on the forefeet and is in this respect intermediate between the specimens from Lake Junín and the one from Ollantaytambo.

In size of teeth the female, type specimen of _M. jelskii_, from Cutervo, shows an approach to the larger-toothed weasels of the northern part of the range of _macrura_.

The specimens in the Riksmuseum from the vicinity of Quito, Ecuador, have been rather fully described by Lönnberg (1921:11-17) and need little comment here, except to say that they show, as he suggested, that the weasel of the Temperate Zone of Ecuador is an intermediate link between _M. f. macrura_ and _M. f. affinis_.

The adult female and juvenal male labeled as from Ambato have little left of the skulls except some of the teeth and the assignment of the specimens to the subspecies _macrura_ is made mainly on geographic grounds. These two specimens probably are part of the shipment of birds and mammals of which Chapman (1926:703) speaks as follows: "A small collection of native-made skins purchased by the American Museum from a commission merchant in New York City as from 'Ambato' proved to be from the eastern slope of the Andes." Another skin in the same Museum, labeled by a native collector as from "Baeza arriba" [= above Baeza] is so dark colored and has the color of the underparts so much restricted, as to suggest that it belongs to the race _aureoventris_. Possibly, therefore, it was taken not at Baeza, Ecuador, which I find to the eastward of Quito at 77° 55' W and O° 25' S, but at some place of the same name on the Pacific Slope, unless the locality has been altogether wrongly recorded on the label. If the specimen was taken near the Baeza above referred to, then it gives evidence of an unnamed race of _Mustela_ on the eastern slope of the Andes, characterized by its dark color. Unfortunately the specimen is young and its skull therefore offers insufficient basis for the judging of its subspecific relationships.

Other specimens, in the British Museum of Natural History, recorded as taken "near Quito" and here tentatively listed under _macrura_, mostly, include specimens so dark colored as to lead me to think they came from country, lower than Quito, adjacent to the range of _aureoventris_.

Nematodes taken from the right frontal sinus of no. 562 from Junín proved to belong to the superfamily Oxyuriodea according to Professor W. B. Herms and Mr. O. L. Williams, who have independently identified them. Because these worms had been dried fifty-five years in the mounted specimen and were later boiled in cleaning the skull, a more accurate determination was impossible and whether or not they pertain to the same species found in North American weasels cannot be said. Of 18 adult skulls examined for this type of infestation, 13 were found affected as judged by the evident malformation of the frontal region.

_Specimens examined._--Total number, 74, arranged by localities
from north to south and unless otherwise indicated in the American
Museum of Natural History.

=Ecuador=: Ibarra, 6600 ft., and 7500 ft., 2[7]; San Antonio,
8000-8500 ft., 5 mi. N Quito, 4 (2[7], 2[78]); Nono, 10000 ft., 1;
Mindo, 1[78]; Zambiza, 8000-8100 ft., NE Quito, 4 (2[78], 2[95]);
Carapungo, 8500 ft, NE Quito, 1[78]; Panecillo, 10000 ft., near
Quito, 2[78]; Guapulo, 8800 ft., 3 mi. E of Quito, 1[78];
Pichincha, 10500 ft., and 12000 ft., 2 (1[78], 1[95]); San
Ignacio, 11500 ft., Pichincha, 1; Santa Rosa, 9600 ft., Río Pita,
2; near Santa Rosa, 9000 ft., 1; Río San Rafel, 9000 ft., 1; N
side Quito, 9000 ft., 1[78]; Quito, 1[4]; near Quito, 5[7]; Nára
Papallacta, 11000 ft., 1[78]; below Papallacta, 9000 ft., 1[78];
Chillo Valley, 1[78]; "Hacienda Hda," 10000 ft., Pintag, Valencia,
1; Baeza arriba, 1; Ambato, 2; San Francisco, 8000 ft., E of
Ambato, 1; Chunchí, Pagma Forest, 6400 ft., 1[1]; Canar, 2600 M.,
1[7]; Malletura, 7600 ft., 1; Contrayerbas, 11000 ft., 1; Sisig,
8500 ft., 3[7]; El Chiral, 1; Almor, 1; Guainche, 3200 ft., 1; no
locality more definite than Ecuador, 4[95]; "Received from Quito,"
1[7]; Quisaya, 6000 ft. (locality not found), 1[7]; La Carolina
(locality not found), 1[78].

=Perú=: La Lejía, 1; Huancabamba, 4 (2[75]); Cutervo, 9000 ft.,
1[73]; Condechacha, 7000 ft., Río Utcubamba, 1[7]; San Pedro,
8600-9400 ft., S of Chachapoyas, 1; Celendín, 1[7]; Junín, 2[73];
Yana Mayo, Río Tarma, 1[7]; Ollantaytambo, 9000 ft., 3 (1[7],
2[91]); Ocabamba, 1[7]; Anta Cuzco, 3400 and 3500 M., 2[4];
Marcapata, 1[91].

=Mustela frenata boliviensis= Hall

Long-tailed Weasel

Plates 28, 29 and 30

_Mustela frenata boliviensis_ Hall, Proc. Biol. Soc. Washington,
51:67, March 18, 1938.

_Mustela frenata macrura_, Hall, Carnegie Instit. Washington Publ.
473:110, November 20, 1936; Hall, Physis, 16:176, 1939 (part).

_Type._--Male, adult, skull and skin; no. 72587, Amer. Mus. Nat.
Hist.; Nequejahuira, 8000 feet, Bolivia; May 19, 1926; obtained by
G. H. H. Tate; original no. 4135 (see plates 28-30).

_Range._--As now known 8000 to 9500 feet in the Andes from
Limbaní, Perú, south to Nequejahuira, Bolivia; upper Subtropical
and Temperate life-zones. See figure 29 on page 221.

_Characters for ready recognition._--Differs from _Mustela
africana stolzmanni_ by absence of median, longitudinal, abdominal
stripe of same color as upper parts; presence of p2 and two roots
rather than one root on P2; from _Mustela frenata macrura_ by
darker color of upper parts (tone 4 or darker of Carbon Brown, pl.
342 rather than tone 3 of Chocolate, pl. 343, Oberthür and
Dauthenay) and lesser size (in males hind foot less than 45 and m1
less than 5.6); from _Mustela frenata agilis_ by darker color of
upper parts (as given above rather than tone 2 of Chocolate, pl.
343, of Oberthür and Dauthenay).

_Description._--_Size._--Male: The type and two young specimens
from Limbaní, Perú, measure respectively, as follows: Total
length, 383, 368, 304; length of tail, 140, 132, 115; length of
hind foot, 43, 44, 41. Tail 55 per cent as long as head and body.
Length of hind foot approximately equal to basal length.

Female: Unknown.

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

_Color._--Top of head blackish posteriorly to behind ears; upper
lips same color as upper parts of head; dark area at angle of
mouth not separated from upper parts as a distinct spot; tip of
tail black; remainder of upper parts near (n) Mars Brown of
Ridgway and tone 4 or darker of Carbon Brown (pl. 342, Oberthür
and Dauthenay); underparts Cream-Colored with strong wash of
Ochraceous-Buff; whitish on insides of forelegs to just below
elbow; color of underparts extended distally on forelegs over
ankles onto antipalmar faces of inner toes, and on hind legs to
knees. Least width of color of underparts averages 15 (11-19) per
cent of greatest width of color of upper parts. Black tip of tail
in type longer than hind foot and amounting to 36 per cent of
length of tail-vertebrae.

_Skull and teeth._--Male (based on the type): See measurements and
plates 28-30. As described in _Mustela frenata macrura_ except
that: Weight, 2.8 grams; basilar length, 41.6; zygomatic breadth
less than distance between anterior palatine foramen and anterior
margin of tympanic bulla; anterior margin of tympanic bulla as far
posterior to foramen ovale as width of 5 upper incisors.

Female: Skull unknown.

_Remarks._--Apparently the first specimens of this race to find their way into a zoölogical collection were the two young males taken on February 17, 1904, at Limbaní, by Geo. Ockenden (sic).

_M. f. boliviensis_ is smaller than any other South American weasel except possibly _agilis_. Better material of the two races probably will show even _agilis_ to be larger.

Early in my study of _Mustela_ after examination of the one young specimen, from Limbaní, in the United States National Museum, an account of this race was drawn up, but the account was discarded for want of satisfactory material and the animal was referred to _macrura_. Then, in 1937, when the two other specimens were studied, the race was formally characterized as different from previously recognized kinds.

The collector has noted on the labels of the two young from Limbaní that they were shot in the afternoon when running together beneath bushes. The frontal sinuses of the type are malformed as a result of infestation by parasites.

_Specimens examined._--Total number, 3, as follows:

=Perú=: Carabaya, Limbaní, 2 (one in U. S. Nat. Mus. and one in
Berlin Zool. Mus.).

=Bolivia=: Nequejahuira, 1 Amer. Mus. Nat. Hist.

=Mustela frenata (?) gracilis= (Brown)

Plates 39 and 40

_Putorius gracilis_ Brown, Mem. Amer. Mus. Nat. Hist., 9(pt.
4):182, pl. 17, 1908.

_Mustela gracilis_, Hay, Iowa Geol. Surv. Bull., 23:32, 1914; Hay,
Carnegie Instit. Washington Publ. 322A:252, October 15, 1924;
Hay, Carnegie Instit. Washington Publ. 390(vol. 2):528, 1930.

_Mustela frenata gracilis_, Hall, Carnegie Instit. Washington Publ.
473:112, November 20, 1936.

_Type._--Adult skull without lower jaws, probably of a female, no.
12431, Amer. Mus. Nat. Hist.; from Conard Fissure, four miles west
of Willcockson, Newton County, Arkansas; obtained sometime in the
period 1903 to 1905 inclusive. (See plates 39 and 40.)

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

_Description._--Skull. Probably female (based on the type): See
measurements and plates 39 and 40; weight unknown; basilar length,
38.1; 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 less than distance from
its anterior margin to foramen ovale; length of tympanic bulla
less than length of rostrum.

_Comparison and remarks._--The type specimen was the only individual referred by Brown (1908) to this species. The remaining material of weasels from this deposit was referred by Brown to his _Putorius cicognanii angustidens_. Examination of the original materials convinces the writer, too, that the specimens, except no. 12431, _are_ of the species _erminea_ [= _cicognanii_ of Brown]. No. 12431 itself may possibly be _erminea_ but is far more probably of the species _frenata_. The uncertainty is due to the fact that an occasional skull alone of a subadult male _erminea_ is extremely difficult certainly to distinguish from a skull alone of an adult female _frenata_. This is true among Recent specimens in the northern Mississippi Valley today; more exactly in Iowa and southern Minnesota the females of _frenata_, oftentimes intergrades between the subspecies _Mustela frenata longicauda_, _M. f. noveboracensis_ and _M. f. primulina_, by only the skulls are next to indistinguishable from certain, unusually slender skulls of male _erminea_. At other places where the ranges of the two species meet, this difficulty is not so often encountered. Also, the type of _gracilis_ has the skull broken in such a way that the postglenoid length in relation to the length of the skull as a whole could not be accurately determined in this particular skull.

The type specimen of _gracilis_ surely is an adult and because of its small size is thought to be a female. Of known long-tailed weasels of the species _frenata_, _gracilis_ is structurally nearest to _M. f. primulina_ which occurs in the same region today and to _M. f. noveboracensis_, the long-tailed weasel of the eastern United States. _M. gracilis_ differs from _noveboracensis_ and agrees with _primulina_ in possessing well-marked temporal ridges which fuse to form a low sagittal crest, in having the mastoid processes projecting farther, laterally, beyond the braincase, in having the anterior ends of the tympanic bullae produced below the squamosal rather than on the same plane with the squamosal, and in having the bullae more inflated anteromedially. _M. gracilis_ differs from both _noveboracensis_ (97 [M] and 56 [F] with skulls of comparable age) and _primulina_ (64 [M] and 24 [F] with skulls of comparable age) in that the zygomatic breadth amounts to less than 58 per cent of the basilar length. Another difference from any one of the skulls of females of _primulina_ is the longer rostrum, which, when measured from the posterior base of the postorbital process of the frontal to the anterior end of the nasal on the same side, amounts to more than 35 per cent of the basilar length. As pointed out by Brown (1908:182) this specimen represents the extreme of slender skull among known kinds of American weasels.

Selected measurements of no. 12431, the type specimen of _Mustela
gracilis_, are as follows: Basilar length of Hensel, 38.1 mm.;
length of upper tooth-rows, 14.3 to 14.4; breadth of rostrum,
11.0; interorbital breadth, 8.5; orbitonasal length, 13.6; mastoid
breadth, 18.2; length of tympanic bulla, 13.0; breadth of tympanic
bulla, 6.3; depth of tympanic bulla, 3.25; outside length of P4,
4.5; inside length of P4, 4.7; breadth of M1, 3.4; length of inner
moiety of M1, 1.8; depth of skull at anterior margin of
basioccipital, 12.2; depth of skull at posterior borders of last
upper molars, 11.3; distance from foramen ovale to tympanic bulla,
3.6 mm.

=MUSTELA AFRICANA= Desmarest

Tropical Weasel

(Synonymy under subspecies)

_Type._--_Mustela africana_ Desmarest, Nouv. Dict. d'Hist. Nat.,
vol. 19, p. 376. 1818.

_Range._--Known from the headwaters of the Amazon in eastern Perú
and from near the mouth of the same river, on its southern side in
Brazil, all within the Tropical Life-zone. See figure 29 on page
221.

_Characters for ready recognition._--Differs from _Mustela frenata_, the only geographically adjacent species of the genus, by: presence of thenar pad on forefoot; presence of a longitudinal, median, abdominal stripe of same color as upper parts; upper lips being broadly edged, entirely round, with color of underparts; failure of longest facial vibrissae to reach posterior margin of ear; absence of p2; relative flatness (see pl. 29, fig. i and pl. 39, fig. _h_) of tympanic bullae.

_Characters of the species._--Size large (total length of adults approximately 500 mm.); foot-soles naked; thenar pad present on forefoot; length of claws, measured on concave sides, less than one and one-fourth times depth of claws measured at bases; longest facial vibrissae not reaching posterior margin of ear; tail relatively long haired; tail at all ages terminating in point as is characteristic of only juveniles and very young of _Mustela frenata_ and _M. erminea_; tip of tail, and muzzle, only slightly darker than remainder of upper parts; upper lips broadly edged with color of underparts; pelage coarse, harsh and sparse; longitudinal, median, abdominal stripe of same color as upper parts present; skull broad and deep; braincase large, rounded, and much inflated anteriorly; palatal region wide; tympanic bullae less inflated than in any other American species of the subgenus; angle of lower jaw reduced; dental formula

3 1 2-3 1
-, -, ---, -; teeth heavy; medial lobe of M1 but slightly larger than
3 1 2 2

lateral lobe. See plates 28, 29, 30, 39 and cranial measurements.

_Geographic variation._--The reddish versus chocolate color of the upper parts constitutes the only variation of a geographic nature so far detected.