attempt to drag it from its hiding-place ceased, and I gave it up for lost; but as suddenly had cause for alarm myself, on seeing what appeared to be a small Snake leaping with great agility about my feet, and springing as high as my knee. I instantly started out of its way, and watched it at a respectful distance, when I found that it was the tail of the animal, which I was not before aware could so easily separate."

From the most popular of the Order, we turn to the most. formidable, the Crocodiles. Of these, the Alligators or Caymans are peculiar to America, the true Crocodiles to Africa, and the Gavials to Asia. The Crocodile of the Nile formed one of the innumerable idols of the ancient Egyptians. His great strength is almost proverbial. "He esteemeth iron as straw, and brass as rotten wood. The arrow cannot make him flee; sling stones are turned with him into stubble; darts are counted as stubble; he laugheth at the shaking of a spear." Yet this formidable reptile is endued with habits which render him one of the great benefactors of the human race, for he frequents the banks of tropical rivers, feeds upon the bloated carcasses which come floating down the stream, and thus, by the removal of carrion, prevents the air from being filled with the injurious effluvia of decaying animal matter.

LET it not excite surprise that in the passage just quoted, the word "fishes" should be applied to reptiles. It is still used by the uneducated in speaking of warm-blooded animals which, like the Whale, live in the sea.

Tortoises are distinguished from all other reptiles by having the body enclosed between two shields, with apertures for the head, the tail, and the four legs. The jaws are horny and without teeth. They may be conveniently arranged with reference to their habits, as Land Tortoises, Freshwater Tortoises, and Turtles or Marine Tortoises.

Fig. 165.-HAWK'S-BILL TURTLE.

Among the latter are the Green Turtle, which is so highly prized by epicures, and the Hawk's-bill Turtle (Fig. 165), which supplies the valuable substance known as the Tortoise-shell of commerce.

The form of the body is admirably adapted for progress

through the water, and the feet are formed into oars of the most perfect construction; so that the ease and celerity of the motions of the animal in the water remind the spectator of the progress of a bird through the air.

Various species of marine Turtles resort annually in immense numbers to the island of Ascension, and the shores of the Gulf of Florida, for the purpose of depositing their eggs. in holes, which they scrape on the beach for that purpose. The poet thus describes the scene:

"The pregnant Turtle, stealing out at eve,

With anxious eye and trembling heart, explored
The loneliest coves, and in the loose warm sand
Deposited her eggs, which the sun hatch'd;
Hence the young brood, that never knew a parent,
Unburrowed, and by instinct sought the sea:
Nature herself, with her own gentle hand,
Dropping them, one by one, into the flood,
And laughing to behold their antic joy,
When launched in their maternal element."

MONTGOMERY'S "PELICAN ISLAND.”

The River Tortoises have webbed feet, and are entirely carnivorous, living upon flesh of various kinds. The Land Tortoises (Fig. 166, 167) have feet with short claws, and are altogether herbivorous, or, in other words, subsist on vegetable food. They are remarkable for their great length of life; and also for the weight which they can carry with apparent ease.

Mr. Darwin mentions the great abundance of Tortoises in all the islands of the Galapagos Archipelago. These creatures sometimes grow to an immense size; he had been told of some so large that six or eight men were required to lift them from the ground. They are LAND TORTOISES.

66

167.-Lower Surface.

fond of water, travel great distances for it to springs on the elevated grounds, and drink large quantities. From this circumstance, it occasionally happens that the inhabitants of the lower district, when overcome with thirst, will kill a Tortoise for the Isake of the contained

water. They believe," says Mr. Darwin, "that these animals are absolutely deaf; certainly they do not hear a person walking close behind them. I was always amused, when overtaking one of these great monsters, as it was quietly pacing along, to see how suddenly, the instant I passed, it would draw in its head and legs, and, uttering a deep hiss, fall to the ground with a heavy sound, as if struck dead. I frequently got on their backs, and then, upon giving a few raps on the hinder part of the shell, they would rise up and walk away; but I found it very difficult to keep my balance."

CLASS III.-BIRDS.

AVES.

"Birds, the free tenants of land, air, and ocean-
Their forms all symmetry, their motions grace."
JAMES MONTGOMERY.

BIRDS are warm-blooded animals, and are produced from eggs. They breathe by lungs, have a heart consisting of four cavities, and a body covered with feathers.

Connected with the higher organization, we see in birds the power of flight in its fullest development. This alone would separate them from any other class of vertebrate animals. It is, of itself, a singular and interesting subject, connected with the feathered tribes. The entire framework of the body shows a beautiful arrangement having reference to this object, and combining strength, flexibility, and light

ness.

The bones of the Eagle, the Swallow, and all others possessed of great powers of flight, are hollow, and can at the pleasure of the bird be filled with air; and as the blood in their bodies is warmer than that of man, the air is particularly buoyant. Birds, too, are furnished with a covering of feathers, which forms their appropriate and peculiar vest