with the mummies of Men, and Apes, and Crocodiles,
concludes them to be the remains of
mammalia and reptiles, that have formed part
of an ancient population on the banks of the
Nile.
SECTION IV.
ICHTHYOSAURUS.
N e a r l y at the head of the surprising discoveries,
which have been made relating to the
family of Saurians, we may rank the remains
of many extraordinary species, which inhabited
the sea; and which present almost incredible
combinations of form, and structure ; adapting
them for modes of life, that do not occur among
living reptiles. These remains are most abundant
throughout the lias and oolite formations
of the secondary series.* In these deposits we
* The chief repository in whieh these animals have been found
is the lias, at Lyme Regis ; but they abound also along the whole
extent of this formation throughout England, e. g. from the
coast of Dorset, through Somerset and Leicestershire, to the
coast of Yorkshire : they are found also in the lias of Germany
and France. The range of the genus Ichthyosaurus seems to have
begun with the Muschelkalk, and to have extended through the
whole of the oolitic period into the cretaceous formation. The
most recent stratum in which any remains of this genus have vet
been found is the chalk marl at Dover, where they have been
discovered by Mr. Mantell : I have found them in the gault,
near Benson, Oxon.
find not only animals allied to Crocodiles, and
nearly approaching to the Gavial of the Ganges;
but also still more numerous gigantic Lizards,
that inhabited the then existing seas and estuaries.
Some of the most remarkable of these reptiles
have been arranged under the genus Ichthyosaurus,
(or Fish Lizard), in consequence of the
partial resemblance of their vertebrae to those
of fishes. (See Plate I, Fig. 51, and Plates
7, 8, 9.) I f we examine these creatures with
a view to their capabilities of locomotion, and
the means of offence and defence, which
their extraordinary structure afforded to them;
we shall find combinations of form and mechanical
contrivances, which are now dispersed
through various classes and orders of existing
animals, .but are no longer united in the same
genus. Thus, in the same individual, the snout
of a Porpoise is combined with the teeth of a
Crocodile, the head of a Lizard with the vertebrae
of a Fish, and the sternum of an Ornithorhynchus
with the paddles of a Whale. The general outline
of an Ichthyosaurus must have most nearly
resembled the modern Porpoise, and Grampus.
It had four broad feet, or paddles, (PI. 7), and
terminated behind in a long and powerful tail.
Some of the largest of these reptiles must have
exceeded thirty feet in length.
There are seven or eight known species of
the genus Ichthyosaurus, all agreeing with one