base on which he is sustained, while walking, is extremely narrow, and is produced by the vertical compression of the body, from which necessarily results greater sureness of foot, while moving rapidly over a narrow surface, than is to be found in those animals whose feet touch the ground at proportionally greater distances. Wilson.

Why are the hind quarters of the ass naturally several inches higher than its fore ones?

Because it is a mountain animal, and this inequality, as in the bare, facilitates its ascent of steep heights. Why is the skin of the ass called' chagrin,' corrupted into shagreen?

Because of its derivation from the Turkish sagri. Wilson.

Its engrained appearance is not, however, natural to it, but is produced by a chemical process.

Why is an ass, eating thistles, vulgarly thought emblematical of the ridiculous?

Because it is related that Crassus, a distinguished Roman, never laughed in his life but once, and that at an ass eating thistles: a circumstance,' says Dr Shaw, by no means ridiculous.'

THE MULE.

Why does the mule bray like the ass?

Because it possesses exactly the same larynx as the ass, without any of the peculiar vocal organs of the mare or mother.

THE MOLE.

Why has it been asserted that the mole does not see? Because, although naturalists have found the eye, anatomists do not find the optic nerve, which, in other animals, serves to transmit the visual sensation to the brain.

Why is not this nerve evident in the mole?

Because it is prevented, by the great extension of the

olfactory apparatus, from following the course which is taken in other animals.

The eye of the mole is very small, in the bulk, at the most, of a grain of millet; in colour, ebony, and hard to the touch. Besides the eye-lid which covers it, it is protected by long hairs, which, crossing one another in all directions, form a thick and closely-woven band.

Why does the breast bone of the mole in shape resemble a plough-share?

Because it may assist the animal in digging under ground.

Why does the fine fur of the mole yield in every direction, and offer no resistance to the touch?

Because the mole may not be impeded in its retreat, while retiring backwards, as it always does upon suspicion of peril, not turning round, which the size of its runs does not permit, but tail foremost, until it arrives at some collateral gallery, when its flight is head foremost, as with other creatures. If this fur had been strong, as in the rat or mouse, it would doubly have retarded the progress of the creature: first, by its resistance, and then, acting as a brush, so as to choke up the galleries, by removing the loose earth from the sides and ceilings of the arched ways. Knapp.

Why is the smell of the flesh of the mole remarkably offensive?

Because its sole food is worms.

It is doubtful whether any other animal exists, which is obliged to eat at such short intervals as the mole. Ten or twelve hours appear to be the maximum of its fasting; at the end of that time, it dies. They are essentially carnivorous: Cuvier tells us that if two moles are shut up together without food, there will shortly be nothing left of the weakest, but its skin, slit along the belly.

Why do mole-catchers draw the body of a captured

mole through their traps, and the adjoining runs and passages?

Because they may remove all suspicious odours, which might arise from the touch of their fingers, the mole's sense of smelling being unusually acute. - Knapp.

Why do mole-catchers tread lightly when in quest of moles?

Because the feeling of the mole is so acute, that, when casting up the earth, it is sensible of the pressure of a very gentle foot; and unless this caution is used, it ceases from its operation, and instantly retires. Knapp.

Why are moles said to be beneficial to vegetation? Because they loosen the soil about the roots of plants. Evelyn and others censure them as injurious; and Buffon accuses them of eating all the acorns of a newly-set soil.

Why are some mole-hills considerably larger than others?

Because the nest or den of the mole is beneath. Why are there no moles in Ireland?

Because, it is supposed, of the dampness of the

soil.

THE BEAVER.

Why have beavers very powerful incisor teeth?

Because they may strip off and divide the bark of the trees, which forms their principal nutriment, and gnaw through thick trunks to obtain the timber for building their habitations. Their teeth are re-produced from the base as fast as they are worn down at the extremity. By good authority it is stated that a beaver will lop off with his teeth, at a single effort, a stem of the thickness of a common walking-stick, as leanly as if done by a gardener's pruning-knife. Why has the beaver a long, broad, flat tail?

Because it may serve in the water, as a paddle and

a rudder, to urge then onwards and to direct them in their course. The stories of the beaver using its tail as a sledge, and as a trowel, are impositions on the credulous. The tail is altogether unfitted for such operations: for mixing up the mud with the rest of the materials, it employs the fore-paws and the mouth. Sec. Zoolog. Soc.

Why is the winter season preferred for taking beavers? Because the winter coat is far superior to the summer. The skin of the young or cub-beaver is the darkest and most glossy, and consequently the most valuable.

Why was the fur of the beaver universally used, at an early period, for making hats?

Because of a proclamation issued in the year 1638, forbidding the use of any materials in making hats, except beaver stuff or beaver wool.

Why do the hind feet of the beaver turn in?

Because it may keep its fur in order, and cleanse it from dirt and moisture, which the beaver could not do if the toes were straight.

THE SEAL.

Why does the seal see equally well under water, as in air?

Because it can lengthen or shorten the axis of the organ of sight at pleasure, and thus see equally well in two media of very different density, viz, air and water.

Why is a species of seal called the sea-lion?

Because of the lion-like mane of the male. Why is another species of seal called the sea-elephant?

Because it has a nose resembling the proboscis of the elephant.

Why is the nose of the seal considered by physiologists to be the most perfect nose belonging to the class of quadrupeds?

Because it has been computed that the smelling surface in the nose of a single seal amounts to the enormous quantity of 240 square inches.

Why is the seal so valuable to the Esquimaux?

Because it furnishes food for his table, oil for his lamp, clothing for his person; even the bones and skins of seals supply materials for his light portable boats, and his summer tents.

Why is the domestication of the seal much easier than that of other animals?

Because its brain is of greater proportionate magnitude than in any other quadruped, and not only does it exhibit in its countenance the appearance of sagacity, but its intelligence is in reality far greater than in most land quadrupeds. It is likewise susseptible of more powerful attachment, and Dr Harwood observes, that, aware of its disposition to become familiar, and this participation in the good qualities of the dog, it is astonishing that mankind have not chosen this intellectual and finely organized quadruped, for aquatic services, scarcely less important than some of those in which the dog is employed on land. — Brande's Journal.

THE ORNITHORYNCUS.

Why is the ornithoryncus called the duck-billed animal?

Because it is distinguished from all mammiferous animals yet known by the unprecedented formation of its jaws, which closely resemble the broad flat bill of a duck, are covered in the same way with a soft membrane, plentifully supplied with nerves for tasting, and also, like it, serrated at the natural edges. The feet are provided with webs, which, in the front ones, project beyond the claws, and can by that means be folded up or expanded like a fan. No appearance of teats has hitherto been discovered in either sex. This wonderful animal lives near the lakes about Botany Bay, in the fifth part of the