c Bodentia. MAMMALIA. Eodentia. 
tlie end of the inaudible tlius singularly three-pronged. 
'I'he external ears, though very small, are provided 
with a distinct auricle.” 'I'he genus has a range 
from British America to Mexico, and from the valley 
of the Mississippi to the Pacific. 
NORTHERN POCKET GOPHER ( Thomomrjs talpoides. 
{Rich.) Baird). — 'I'liis is very nearly the color of the 
llouse-rat. Its length is about six to eight inches. 
Its range is from Hudson’s Bay to the Rocky Moun- 
tains, mostly on the west side of the Mississippi 
River. 
PACIFIC POCKET GOPHER {Th. talpoides Imlhiv- 
orus, {Rich.) Goues). — 'This is Geomys douglassi of 
HeKay, in New Yorh Report on Mam., and the 
same of Baird and Richardson. Its size is rather 
more than the last-mentioned species. 'The hand is 
somewliat shorter than the foot, owing to the claws 
being shorter. Habitat, Pacific Coast, from Wash- 
ington 'I'erritoi'y to California. 
SOUTHERN POCKET GOPHER {Th. talpoides urn- 
hriniis, {Rich.) Goues). — 'I', fulvus of Baird, who also 
describes the present species. DeKay lias it Geomys 
umbrinus. It averages smaller than either of the 
preceding. 'I’he length is about six inches. 'I’he 
fore-feet are decidedly less than the hind-feet. “'I’he 
color varies from a uniform rich fawn to tawny- 
brown shades, with or without a blackish dorsal 
area. It is occasionally quite gray, sometimes a 
lustrous coal-black all over.” Habitat, much as the 
preceding. 
ROCKY MOUNTAIN POCKET GOPHER {Th. elusius. 
Goues). — This is the smallest known species. Its 
length is about five inches. 'I’he feet are remarkably 
small ; the fore-claws weak, small and little curved. 
'I’he muzzle is almost entirely hairy, with a very 
small, naked pad between the nostrils. 'I’he tail is 
very short. 'I’he ears are minute. Its color above 
is a pale yellowish-gray, with a slight light brown 
shade-; below, it is nearly white. 'I'he feet and tail 
are white. End of snout blackish. 'I’he cutting- 
teeth are orange colored on the exterior. 'I’he mam- 
mse are twelve in number. Like some other instances, 
this is so rare, or has so entirely esca])ed the atten- 
tion of naturalists, that, at the time of publish- 
ing Dr. Goues’ Memoir on these animals (who also 
described this species), there vvas but owe specimen 
to examine; this was found by Dr. Win. A. Ham- 
mond, then Asst. Surgeon U. S. A., at Bridger’s 
I’ass, Rocky Mountains, in 1857. It is now in the 
Museum of the Smithsonian Institute, Washington, 
and bears the number 3051. 
Seutes 111. — Hystuicomorpiia : Hystricine Rodents. 
Fa.miia— HYSTRICH)^. 
'I’he term Hystrix suggests the family designation, 
meaning simply, I’orcupine. 'I’he Porcupines of the 
Old and New Worlds have been separated into two 
distinct families, although there is a marked resem- 
blance. 'I’he latter differ from the former in having- 
perfect clavicles ; in the tail (with the exception of 
Erethizon) being prehensile, more or less; in the 
molar-teeth being fully rooted ; in having less than 
five toes to all the feet ; in having- tuberculate soles; 
in the undivided upper lip; in a peculiar foiin of the 
lachrymal bone; and in some more or less important 
particulars of osteology. 'I’he skull differs in certain 
features from that of t he Old World forms. 
In South America certain forms are indigenous, 
which have been arranged under the sub-family title 
Synetherinm; the genus Erethizon, which belongs to 
it, is the only one found north of Mexico. 
Erethizon. — F. Gorier. 
North American Porcupines. 
'I’his genus is characterized by having four toes on 
the fore-feet, the hind being furnished with five. 
'I’liey are all armed with stout curved claws. The 
tail is short, thick and depressed ; is not prehensile, 
and is beset on the top, at the base, with thick 
hairs and spines, and on other parts with rigid 
bristles. 'I’he limbs are short but strong. It em- 
braces the largest of the American forms. Another 
character is seen in the close approximation of the 
nostrils. 'I’his, with the Porcupines of the Old 
W'orld, formally comprised one genus, but the osteo- 
logical features, particularly those of the cranium, 
are strikingly different. 'I’he present genus is repre- 
sented by only one species, divisible, however, into 
two well-marked geographical varieties. 
CANADA PORCUPINE [Erethizon dorsatus, {Linn) 
F. Guv.) — Plate H, fig. vi. — 'I’his creature, though in- 
digenous to our land, is probably less known to 
most people than the African species, which, from 
time immemorial, has been the Porcupine to the read- 
ers of Natural History books. 'I’he quills of the 
“ fretful Porcupine ” are familiar objects, and the I'ull- 
fledged “ Corkintine” of “Patrick” is no less so to 
the visitors of menageries and zoological gardens. 
'I’he American form has been kept alive in Central 
Park, New York, but its habits are such that few 
obtain a fair view of the creature. 'I’he notion, 
embraced almost universally, that these creatures 
“throw their quills” is wholly incorrect. 'I’he quills 
of the upper surface of the tail are loosely set 
in the epidermis, and their outer ends are barbed. 
’I’he animal, when irritated, turns its tail towards 
the object, and, with rapid strokes, drives the quills 
into the flesh ; the hold of their roots being so 
slight, and the barbs cling so closely, that the 
weapons are , left in the wounds. We observed an 
Erethizon, which was confined in a small box with a 
half-grown Hare; both were evidently in fear, and 
clung closely to opposite corners. A momentary 
change of position caused the Hare to receive the 
full effects of the barbed battery of llirethizon. 
Myriads of the small missiles were seen thrust into 
the skin. 'I’he old keeper at Central Park afiirmed 
stoutly that he “see ’em fly.” Nevertheless, the 
truth remains — the quills must come in contact 
with some yielding- object to sever their connection 
with the animal. 'I’he Lrethizon is called Cawquaw 
by the Indians of the North-west, and Ur.sou in some 
regions. Emmons, in Mass. Report on Mammals, 
