SAURIANS. 173 
the gavial and the alligator—have left to the dolphins, the 
sharks, and other monstrous or swiftly-swimming cetaceans 
and fishes the dominion of the seas, und now merely infest 
+he rivers and swamps of the tropical zone. The lizards also 
have long since retired from the scene where they once 
abounded, and the ocean at present harbours no other reptiles 
in its bosom than turtles and sea-snakes. 
Most of the animals belonging to this class are either dan- 
gerous or of a disgusting appearance. Few creatures are ob- 
jects of such universal abhorrence as the crocodile—the very 
type of brutal cold-blooded ferocity ; as the venomous snake— 
the emblem of perfidy and ingratitude ; or as the loathsome, 
but innocent toad, to which, on account of its ugliness, noxious 
properties have been ascribed which the poor animal does not 
possess. The frogs, lizards, and turtles alone seem to have 
escaped this general detestation, either from their more active 
habits, or their well-known harmlessness, or their various utility 
to man. 
The anatomy of the turtle offers many points of interest; its 
vertebra, ribs, and breast-bone growing together so as to form a 
bony envelope round the whole animal. This harness is covered 
by the skin, which in its turn is bedecked with large scales, while 
all the muscles and other soft parts are enclosed in the inner 
cavity. Only the head, feet, and tail protrude through openings 
between the upper and under carapace, and these can, by the 
land tortoises at least, be withdrawn entirely under the former. 
This is the only protection which Nature has afforded these 
animals against their enemies, for they have neither swiftness of 
flight, nor any offensive weapon at their command. But as soon 
as anything suspicious approaches, they conceal themselves 
under their massive cover, and oppose to every attack by tooth 
or nail the passive resistance of an impenetrable shield. Most 
of their enemies find it, besides, no easy task to turn them on 
their back, as many species attain a very considerable weight, so 
that their mere bulk constitutes a good defence. It might be 
supposed that this protection could only avail for a short time, 
as the want of air must soon force the animal to stretch its head 
out of its hiding-place, and this indeed would be the case, if kind 
Nature had not taken her measures against this emergency, by 
giving the creature a cold blood, so that it can remain a very 
