Until a very recent period the animals composing this family were quite
unknown, or perhaps we ought rather to say they were just sufficiently
known to make them the objects of superstition. Seeing that there is in
their general appearance, somewhat of a resemblance to the human form,
the casual glimpses obtained of them at once satisfied their first
discoverers that they were Tritons and Sirens, such as they had read of
in mythological writings, and the belief in the existence of Mermaids
and Mermen was thus at once confirmed.
In the works of Gesner, Aldrovandus and Jonston, the earliest authors
after the renaissance of Natural History in modern times, the figures of
creatures having human bodies joined with the tails of Fishes are
inserted with the utmost faith in their existence.
A more accurate acquaintance with these strange creatures has, however,
revealed to later voyagers that they are merely a race of animals very
closely allied in their organization to Whales, which in form they
closely resemble, while their internal structure shows them to be still
more nearly related to the gigantic Pachyderm Quadrupeds, such as the
Hippopotamus and the Tapir.
The main feature which distinguishes the Herbivorous Cetaceans is their
total want of hind limbs, a circumstance in which they resemble the true
Whales and Dolphins; but in the structure of their nostrils they conform
to the usual arrangement met with in four-footed Mammalia. Instead of
whalebone or the sharp conical teeth of the Dolphins, they are furnished
with broad, flat grinders, wherewith they chew their vegetable food,
which consists principally of the sea-weeds, etc., abundant near the
shores which they frequent. In short, as Buffon well expresses it, these
creatures terminate the list of terrestrial quadrupeds and commence the
history of the population of the sea, or, more correctly, form the
connecting link between the Mammiferous inhabitants of the ocean and
those of the river and the marsh.
This family comprises the Manatees and the Dugongs.