145            Townsend's Shrew Mole

                          SCALOPS TOWNSENDII.--BACH.
                             [Scapanus townsendii]

                             TOWNSEND'S SHREW-MOLE.
                               [Townsend's Mole]

                              PLATE CXLV.--MALES.


     S. Magnitudine S. aquatico duplo major, supra rufo-fuscus.  Dentibus XLIV.


                                  CHARACTERS.

     Double the size of the common Shrew-Mole, with eight more teeth than that
species; dark liver colour.


                                   SYNONYMES.

     COMMON MOLE.  Mackenzie's Voyage to the Pacific, &c., p. 314.
     MOLE.  Lewis and Clark, Journey, vol. iii. p. 42.
     SCALOPS CANADENSIS.  Rich., Fauna Boreali Americana, p. 9.
     SCALOPS TOWNSENDII.  Bach., Jour. Acad. Nat. Sci., vol. viii., part 1,
       p. 58.


                                  DESCRIPTION.

                                    2         6-6         4-4
          Dental Formula.--Incisive -;  Canine ---; Molar --- = 44.
                                    4         6-6         3-3

     In the upper jaw the incisors are large, and a third higher than the canine
teeth usually termed false molars, which immediately follow them; these are
succeeded by three small teeth of a nearly conical shape, increasing in length
from the first to the third; the fourth false molar on each side is the
smallest; the fifth is a little larger in size, and slightly compressed; the
sixth still larger, and has a considerable posterior projection; the four
posterior cheek teeth, or true molars, are much larger and higher than the
anterior ones; the first of these (which we have called a canine tooth) is
rather small, and bilobed, with a small internal tubercle; the second and third
are the largest and nearly resemble each other, exhibiting three distinct
points, two external and posterior, and one anterior, the external ones being
the longest, and the last molar being the smallest, and of a triangular form; in
the lower jaw there are two very small incisors in front; next to these are two
of a considerably larger size, which, although we have called them incisors, are
nearly of the same shape and appearance as those which succeed them.
     The canine or false molars, six on each side, are nearly the same size, and
incline forwards; the three true molars, which succeed, are large, nearly
uniform in size, and correspond with those in the upper jaw, although they are
smaller.
     Body, thick and cylindrical, shaped like the Shrew-Mole (Scalops
aquaticus); the limbs are short, being concealed by the skin of the body nearly
down to the wrist and ankle-joints.
     Palms, naked, very broad, furnished with moderately long nails which are
channelled beneath; tail, rather thick, tapering from the root to the tip, and
nearly naked, being very sparingly clothed with short hairs; the vertebrae are
equally four sided; fingers, very short, united to the roots of the nails;
nails, slightly curved; hind-feet, more slender than the fore-feet, and
distinctly webbed to the nails; the feet are thinly clothed above, with short
hairs.  The whole of the body, both upper and lower surface, presents a velvety
appearance.


                                    COLOUR.

     The body is dark liver brown colour above, changing with the light in which
it is viewed to silvery or black shades; the hair when blown aside exhibits a
grayish-black colour to near the tips, which in some of the points are white,
others brown black, producing the changeable colours above described.  One of
the specimens which we have seen--the one figured in our plate--has a
whitish-yellow stripe about two lines wide, running in a somewhat irregular line
along the under surface of the body to within an inch and a half of the
insertion of the tail; there is also a white streak commencing on the forehead,
spreading over the snout and around the edges of the mouth and lower jaws.  The
teeth are white; feet, point of nose, and tail, flesh colour; nails, light
brown.


                                  DIMENSIONS.

                                             Inches.    Lines.

     Length of head and body, .  .  .  .  .  .  8         6
     Length of tail, .  .  .  .  .  .  .  .  .  1         6
     Breadth of palm,.  .  .  .  .  .  .  .  .  0         7


                                    HABITS.

     We were informed by NUTTALL and TOWNSEND, who mistook this species for our
common Shrew-Mole (Scalops aquaticus), that they dug and formed galleries, and
threw up little mounds of earth precisely in the manner of that animal.  They
are well known to the farmers and settlers in the valleys of Oregon, as they
traverse their fields and gardens, cutting up the ground in some places to an
injurious extent.


                           GEOGRAPHICAL DISTRIBUTION.

     This species is found in considerable abundance near the banks of the
Columbia and other rivers in Oregon, where our specimens were obtained.  We are
unable to say what is the northern limit of this animal.  It has not yet been
found on the eastern side of the Rocky Mountains, and we have not been able to
determine positively that it exists in California but we have little doubt that
it is the most common Shrew-Mole on the Pacific side of the North American
continent, where our common species (Scalops aquaticus) does not appear to have
been discovered.


                                GENERAL REMARKS.

     Sir JOHN RICHARDSON, who first described this animal from a specimen
preserved in the museum of the Hon. Hudson's Bay Company, obtained by Mr. DAVID
DOUGLAS, does not seem to have made a comparison between this Mole and our
common Atlantic species.  HARLAN had described the skull of the species which we
have since described and figured as Scalops Brewerii, having forty-four teeth,
and another which had thirty-six.  RICHARDSON was thus induced to suppose that
authors had varied in their descriptions of the Scalops from their having
mentioned edentate spaces between the incisors and grinders, and had
consequently described the young in those specimens which had only thirty-six
teeth.  The young, however, of our common aquaticus (or as CUVIER has called it,
Scalops Canadensis) has only thirty teeth, the adult thirty-six, whilst the
present species has forty-four.
     On our pointing out to Sir JOHN RICHARDSON these particulars, he expressed
himself gratified to have an opportunity of correcting the error into which he
had inadvertently fallen.