tion is broad and short; the malar portion of the zygomatic arch
has no inferior angular process as in the _Octodontidae_; the
occipital plane or hinder-surface is perpendicular, with a median
ridge; the incisor teeth are large and powerful; the molars with
external and internal folds, four in each jaw. The form is robust;
limbs sub-equal; fore-feet with four toes, and a small wart-like
thumb; hind-feet with four and five toes; tail long in some, short
in others. There are two sub-families--_Sphingurinae_ and
_Hystricinae_. With the genera of the first we have nothing to do.
They include the prehensile-tailed porcupines of South America,
_Sphingurus prehensilis_, _S. villosus_, and _S. Mexicanus_, all
arboreal forms, and the Canada porcupine (_Erythizon dorsatus_)
which is covered with woolly hairs and spines intermixed. The true
porcupines, sub-family _Hystricinae_, consist of two genera, both
of which are represented in India--_Atherura_ and _Hystrix_.

[Illustration: Skull of Porcupine.]

SUB-FAMILY HYSTRICINAE--THE TRUE PORCUPINES.

Grinding teeth semi-rooted; skull rather more elongate;
infra-orbital foramen of great size; clavicles imperfect, attached
to the sternum, and not to the scapula; upper lip furrowed; tail not
prehensile; soles of feet smooth. The female has six mammae. In these
points they differ from the American arboreal porcupines
(_Sphingurus_), the skull of which is very short, the tail prehensile,
the soles of the feet tuberculated, and the female has only four
mammae.

The two genera, _Atherura_ and _Hystrix_, which compose this
sub-family, are distinguished by long tail and flattened spines
(_Atherura_); and short tail and round spines (_Hystrix_).

_GENUS ATHERURA--THE LONG-TAILED PORCUPINE_.

Nasal part of skull moderate; upper molars with one internal and
three or four external folds, the latter soon separated as enamel
loops; the lower teeth similar but reversed; the spines are flattened
and channelled; the tail long and scaly, with a tuft of bristles at
the end.

NO. 402. ATHERURA FASCICULATA.
_The Brush-tailed Porcupine_.

HABITAT.--Assam, Khasia hills, Tipperah hills, Burmah, Siam, and the
Malayan peninsula.

DESCRIPTION.--"The general tint of the animal is yellowish-brown,
freckled with dusky brown, especially on the back; the spines, taken
separately, are brown white at the root, and become gradually darker
to the point; the points of the spines on the back are very da