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, and now merely infest 

 the 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 havo 

 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 

 vertebrae, 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 land tortoises at least, be withdrawn entirely under the former.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 



