Ixxxix 
Rodentia. MAMMALIA. Eodentia. 
obsolete; tlie tail slender and rounded, as indicated 
by its specific name. As yet only three specimens 
are known to science ; those are the ones described 
by Prof. Baird, in 1857, which were brought from 
Fort Yuma by Gen. G. H. 'I'homas. 
SONORAN SPERMOPHILE {S. spilosoma, Bennet). 
— This species was found by Mr. Bennet in “ that 
part of California which joins Mexico.” Audubon 
and Bachman describe it as S. inexicanus. Its 
lengtli is six and a half to seven inches. It is rare 
in collections, though it is said to be abundant in 
the region of the Gulf of California, and as far east 
as El Paso, and northward to Fort Stanton. 
KENNICOTT’S SPERMOPHILE {S. obsoletus, Kenni- 
cotf). — This is closely allied to the preceding, its form 
and size being the same. Its color is a dull yellowish- 
brown, indistinctly spotted with lighter, the spots be- 
ing bordered with black posteriorly. The ears are 
nearly obsolete. The tail is terete near its base, and 
broad and tufted at the end. Its habitat is in Utah 
and the neighboring region. 
THE MEXICAN SPERMOPHILE {S. mexicamis, 
Liclit., Wagner). — 'J'his form was first found in Me.x- 
ico, but is now known on the Texan side of the Rio 
Grande. Its size is eight to eight and a half inches 
in length; tail to end of hairs five and three-quarter 
inches. The color is similar to others, “ with numer- 
ous lines of subquadrate spots of white.” The ears 
are small, but distinct. The pelage is coarse and 
stiff. 
STRIPED SPERMOPHILE {S. tridecemlineatus, 
{Mitchell] And. and Bach.) — This species is met 
witli as far east as Minnesota, and it extends west- 
ward to the Rocky jMountains, and southward to 
Missouri and Western Texas. Latterly it is seen as 
far east as Xorthern Ohio. Two varieties are known — 
one called pallidus, rather smaller. “In the pattern 
of coloration this quite strongly resembles the S. 
inexicanus. 'I'he latter is smaller, and has a longer 
tail ; it also differs in some characters of skull.” 
FRANKLIN’S SPERMOPHILE {S.franldini, Saline, 
Lesson). — -Tliis is also called the Gray-Headed Sper- 
MOPHiLE. It is about ten indies in length; the tail 
to end of hairs six and a quarter to eight and a half 
inches. No species is so strongly marked as this, 
and, consequently, it is not confounded with any 
other. It seems to have been quite unknown to 
Audubon and Bachman, though quite common in 
Illinois and Wisconsin. Mr. Jillsou, formerly of 
Lynn, Mass., and now of Tuckerton, N. J., has 
communicated to Mr. Allen’s Monograph on Rodentia 
some very interesting facts concerning its introduc- 
tion into T'uckerton, in the State of New Jersey. 
He says that a single pair were introduced there in 
1867, when they escaped. The same species, in con- 
siderable numbers, are now found nine miles from 
that place, and also four miles south of the same. 
“ 'I’liey are very common on all the farms in Tucker- 
ton, and seem always to keep in the fields, as I have 
never seen them in the woods. I find very little dirt 
at the mouths of their burrows, sometimes none. 
They destroy young chickens and turkeys.” They 
are called Gophers in that region. It is a remark- 
Yoi/, I. — tn. 
able circumstance that in ten years the offspring of 
one pair of these animals should spread over so large 
a tract. 
ANNULATED-TAILED SPERMOPHILE [S. annuU- 
tus, And. and Bach.) — -This species was first described 
by Audubon and Bachman, in 1842. It is a Mexican 
form, and rather rare. 'I'he general form is very 
much like the Squirrels. 'The ears are broad, fully 
a half an inch high, and rounded above. 'I'he tail is 
nearly the length of the body, including the hairs. 
The length of the body is nine and a half inches. 
Cynomys. — Raf. 
'This genus, like the preceding, has been variously 
named: as Arctomys, Spermophilus, Anisonyx, etc. 
The generic characters are seen in the “rather short 
skull, which is broad, highly arched and massive. 
'I'he upper premolars are two, the first large. 'I'he 
dentition is heavy. 'I’he grinding-teeth, except the 
first preinolar and last molar, liave the transverse 
breadth twice the antero-posterior. The last molar 
is much larger than the others. 'I'he cheek pouches 
are of moderate size. 'I'he tail is very short and 
flattened ; the ears rudimentary ; the polle.x large, 
with a well-Jeveloped nail ; the pelage short, full and 
soft ; the coloration without spots or streaks.” 'I'his 
genus is especially characterized by the massive 
dentition ; there is also a remarkable convergence of 
the upper molars. It is represented by only two 
species ; those are confined to the parks and plains 
of the great mountain plateaux. 
THE PRAIRIE HOG {Cynomys ludovicianus.{Ord) 
BairL). — Plate H, fig. vii. — Called also the Missoaiu 
Barking Squirrel. Godman calls it the Prairie 
Marmot ; Richardson the Wistonwish ; and Say the 
Louisiana Marmot. 'I'he length of this creature is 
about twelve inches, with a tail about five inches, in- 
cluding the hairs. Lewis and Clark first met with it 
on the banks of the Missouri River, in 1804. 'I'he 
eastern limit of its range is near the ninety-eighth 
juirallel. 'I'he Prairie Dog is an interesting pet, as 
it readily becomes domesticated. Specimens are 
kept at the Central Park Gardens, New York, where 
they amuse greatly by their curious habits, 'riiough 
called Barking Squirrel, it nevertheless does not 
bark, but emits a true sciurine voice. It is also far 
from being dog-like. It does not inhabit, willingly, 
the same burrow with the Rattle-snake and Owl, as 
is so commonly believed ; the latter simply chance 
to occupy the deserted holes of the “ Dogs.” 
THE WESTERN PRAIRIE DOG {G. colamlianus, 
{Ord) Allen) is the Arctomys lewisi of Audubon and 
Bachman, and Short-'Tailed Prairie Dog of Baird. 
'I'he length of this form ranges from nine and a half to 
eleven and a half inches. 'I'he tail is very short and 
flattened, usually a pure white. This is a smaller 
animal than the preceding, with the tail about one 
half the length of the same in that species. It is 
confined to the region west of the Rocky Mountains. 
Like the other species, it lives in large companies, 
sometimes two hundred acres being populated by 
them. Each burrow has ten or twelve occupants. 
'I'he earth thrown up from the excavations form 
