THE JERBOA. 113

another passage, to within a short dis-
tance from the surface, through which
they can escape. It is almost impossible
to kill them, except by coming on them
unawares. The Arabs, however, take
them alive, by stopping up all the out-
lets of the different galleries belonging
to the colony, with the exception of one,
through which they force them out. They
keep within their holes during the day.
sleeping rolled up, with their heads be-
tween their thighs. At sunset they come
out, and remain abroad till morning.
They go on their hind legs only, the fore
legs being very short; their motion is
nevertheless, very rapid, being effected by
leaps of six or seven feet, so rapidly that

it is almost impossible to overtake them.
8