The Donaldsonville chief. [volume] (Donaldsonville, La.) 1871-current, 1912-08-03

260 species OF Mus described bofore
1905. Since that date 8 number Il
new forms have been described :
The genus Mus il characterizad II
narrow, ungrooVed* incisors. fhres
small, rooted molars; soft fur mivad
with hairs, sometimes with spines: !
rudimentary pollex having a short
nail instead of a claw; a long fail
bearing rings OF Overlapping scalas
and often naked Or nearly. so. The
ears are rather large. the avas
bright and prominent, and the m,1zzla ~,
somewhat pointed. The members Of
the genus are natives of the old
World, throughout which. with The
exception of Madagascar. thew Are
quite generally distributed. Nearly
seven-eighths of the whole number Of
species are commonly called rats.
The distinction between rats and
mice is arbitrary and based on size,
Exclusive of the tail, rats NAV be
said to vary IN length from q 10 TO
10 inches or more, while mice meas
ure from 2 to inches. With few
exceptions, rats have six Well-defined
footpads (plantar tuhercles). the last
on the hind foot being elongated in
shape; the last hind foot pad Of mice
is usually circular.
Of the many species OF Mus onIy
three or four have Developed the
ability to adapt themselves to such
a variety of conditions as to become
cosmopolitan. Four have found Iodg-
ment in America The common
house mouse (Muss musculusl. the
old English black rat (Mus rattus1:
the Egyptian or roof rat, (Mus alex
andrinus): and the brown rat Mus
norvegicus1, known also as the gray
rat, barn, rat, wharf rat, sewer rat.
and Norway rat. The black rat and
the roof rat differ from each other
chiefly in color. Indeed some zoolo-
gists regard them as races of the
same species, and the trinominal
Mus rattus alexandrinus for the roof
rat is now in use among biologists.
Distribution Of The Genus Mus IN /
America.
The common house mouse IN.
found its way to America
soon after the first settlement by
Europeans. 1t now inhabits all seE
led parts Of North and South Amer
ca, as well as nearly the entire Old
World; but in very cold regions it I
ioes not always survive the winters,
Ind is therefore comparatively scarce
or local. It almost always reaches a
The black rat NC rattus) has been
Known in SEurop since the twelfth
century Il was carrIsy to South
Ie na W. .Pa3t three and
i tint s55 s5i5 Thg
inle of its arrivasss q III English col
,nies Of North America. is not known
With certainty, but 1t was we'll estab-
ished in the settled parts by the
BEGINNING of the eighteenth century.
Soon after the arrival Of the brown
at, the black species began to de-
'rease in numbers, and has become
'xtinct in most localities. At pres
mt it is not uncommon IN some parts
# the south, and still occurs in
catered colonies in Canada and
ome of the states east of the Mis-
issippi, and also on some Of the
coastal Islands. 1t is oecasioned
d many Of our seaports, being appar-
ntly brought from the Far East
n merchandise. Except in few
,orts like San Francisco, where new
.rrivals are probably rather fre-
.uent, these introduced individuals
re often destroyed before they null
i,1r r.f ~. IL 4 Il
n Europe and its disapp be-
ore the brown rat Is an exact par
tllel to its history here, and the ami
nal is now comparatively rare north
f the Alps, except in the Channel Is
ands.
The biological survey has speci-
nen of the black rat from Massa-
New Hampshire, Georgia.,
florida, Alabama, California and
Washington, and also from Mexico,
honduras, Nicaragua, and Hawaii.
here are authentic records of its re-
ent occurrence in Newfoundland,
ouebec, Nova Scotia, New York,
lorth Carolina, Tennessee, West
rirginia, and Mississippi. In parts
f South and Middle America 1t is
bundant.
The roof or Alexandrian rat (M.
lexandrinus) is similar to the black
at in form and general habits,
hough not in color. Little is known
its history, but it is thought to be
native of Egypt, where it is still +
bundant. 1t has established itself Fl
i many parts of sthe world, mainly
II Il
fnop+in,,od nm mage eight