draws an inspiration, and dives gently down, head foremost. This
mode of proceeding distinguishes the Tucuxi at once from the
other species, which is called Bouto or porpoise by the natives
(Inia Geoffroyi of Desmarest). When this rises the top of the
head is the part first seen; it then blows, and immediately
afterwards dips head downwards, its back curving over, exposing
successively the whole dorsal ridge with its fin. It seems thus
to pitch heels over head, but does not show the tail fin. Besides
this peculiar motion, it is distinguished from the Tucuxi by its
habit of generally going in pairs. Both species are exceedingly
numerous throughout the Amazons and its larger tributaries, but
they are nowhere more plentiful than in the shoaly water at the
mouth of the Tocantins, especially in the dry season. In the
Upper Amazons a third pale flesh-coloured species is also
abundant (the Delphinus pallidus of Gervais). With the exception
of a species found in the Ganges, all other varieties of dolphin
inhabit the sea exclusively. In the broader parts of the Amazons,
from its mouth to a distance of fifteen hundred miles in the
interior, one or other of the three kinds here mentioned are
always heard rolling, blowing, and snorting, especially at night,
and these noises contribute much to the impression of sea-wide
vastness and desolation which haunts the traveller. Besides
dolphins in the water, frigate birds in the air are
characteristic of this lower part of the Tocantins. Flocks of
them were seen the last two or three days of our journey,
hovering above at an immense height. Towards night, we were
obliged to cast anchor over a shoal in the middle of the river to
await the ebb tide. The wind blew very strongly, and this,
together with the incoming flow, caused such a heavy sea that it
was impossible to sleep. The vessel rolled and pitched until