os making their beds round the fire,
have left in my mind a strongly-marked picture of this first night,
which will never be forgotten.

The next day the country continued similar to that above described.
It is inhabited by few birds or animals of any kind. Occasionally a
deer, or a Guanaco (wild Llama) may be seen; but the Agouti (Cavia
Patagonica) is the commonest quadruped. This animal here represents
our hares. It differs, however, from that genus in many essential
respects; for instance, it has only three toes behind. It is also
nearly twice the size, weighing from twenty to twenty-five pounds.
The Agouti is a true friend of the desert; it is a common feature
of the landscape to see two or three hopping quickly one after the
other in a straight line across these wild plains. They are found
as far north as the Sierra Tapalguen (latitude 37 degrees 30'),
where the plain rather suddenly becomes greener and more humid; and
their southern limit is between Port Desire and St. Julian, where
there is no change in the nature of the country.

It is a singular fact, that although the Agouti is not now found as
far south as Port St. Julian, yet that Captain Wood, in his voyage
in 1670, talks of them as being numerous there. What cause can have
altered, in a wide, uninhabited, and rarely-visited country, the
range of an animal like this? It appears also, from the number shot
by Captain Wood in one day at Port Desire, that they must have been
considerably more abundant there formerly than at present. Where
the Bizcacha lives and makes its burrows, the Agouti uses them; but
where, as at Bahia Blanca, the Bizcacha is not found, the Agouti
burrows for itself. The same thing occurs with the little owl of
the Pampas (Athene cunicularia), which has so often been described
as standing like a sentinel at the mouth of the burrows; for in
Banda Oriental, owing to the absence of the Bizcacha, it is obliged
to hollow out its own habitation.

The next morning, as we approached the Rio Colorado, the appearance
of the country changed; we soon came on a plain covered with turf,
which, from its flowers, tall clover, and little owls, resembled
the Pampas. We passed also a muddy swamp of considerable extent,
which in summer dries, and becomes incrusted with various salts;
and hence is called a salitral. It was covered by low succulent
plants, of the same kind with those growing on the sea-shore. The
Colorado, at the pass where we crossed it, i