The animals of one genus* have teeth without the folds so commonly observed in thcse of other animals. Wo give an engraving of these, and also of one species.

Very different are the teeth of another genus,t a representation of a species of which we have already given, and which M. E. Geoffroy describes as a kind of mouse.§

A third genus contains the animals peculiar to Africa.

Only one species is found in

Gambia.l

THE GIGANTIC RAT.P

Tuis animal has the appearance of the brown rat, dilated to gigantic proportions. On the upper parts the hair is thickest and black, beneath it inclines to gray. A female weighed two pounds eleven ounces and a half. Its total length was twenty-six and a quarter inches, of which the tail measured thirteen inches. The male grows larger, and weighs three pounds and upwards.

The gigantic rat is found in many places on the coast of Coromandel, in Mysore, and in several parts of Bengal, between Calcutta and Hurdwar. It is partial to dry situations, and is hardly ever found distant from habitations. The lower caste of Hindoos eat the flesh of this rat in preference to that of any other species. It is a most mischievous animal, burrows to a great depth, and will pass under the foundations of granaries and storehouses, if not deeply laid. Mud, or unburnt brick walls, prove

REITHRODON COMICULOIDES.

no security against its attacks, and it commonly perforates such buildings in all directions. It is

destructive in gardens, and roots up the seeds of all leguminous plants sown within its haunts. Other plants and fruits suffer by its depredations. When grain and vegetables are not within its reach, or scarce, it will attack poultry, but the former are its choicest food. Its geographical range is, most probably, very extensive.

• Dendromys.

† Acomys.

+ See page 216. Cricetomys Gambianus. Waterhouse.-The Goliath Rat. Ruppell.

§ Mus cahirinus. Mus giganteus. Hardwicke.

The last genus § has the muzzle rather pointed, the ears small and rounded, the body covered with long hairs, the tail long, cylindrical, and rather scaly, with scattered hairs. There are four toes and the vestige of a thumb on the fore feet. The hinder feet are five-toed. The molars have the crowns divided into obliquely quadrangular lobes, the summits of which are hollowed into a spoon shape.

The fur of the specimen we give is short, soft, maroon brown above, and white below; the tail is black at the base and white at the other extremity. The size is sometimes twice that of the common brown rat.

Reithrodon. Waterhouse.

† Hapalotis.

Hydromys. Geoffroy.

THE type of the Mainmalia may be considered as having reached its full development in the tribes comprehending the larger beasts of prey, at which we have now arrived. The tribes into which this Order is divided differ considerably in their habits and manners, and present a group much less bound together by strongly-marked features, than we have found to be the case in other circumstances, as, for instance, among those of the Four-handed Animals. For while many inhabit the earth's surface, or dwell in its holes and caverns, others, on the contrary, tenant the sea, and prey on the finny tribes of the waters.

Though one of the chief peculiarities of this order, and from which it derives its generic title, is the living on flesh, still this fact is not an universal characteristic; for, in one family, at least, the diet consists chiefly of vegetable substances, to which flesh is only occasionally added. The differences in habits and structure, which occur in this order, prevent the possibility of arranging the genera in a line perfectly unbroken and uniform, but rather conduce to the distribution into families branching out from a common centre, and connected among themselves by various and multiform ties of relationship. Still, there are resemblances which are specially worthy of notice.

As, generally, these creatures subsist on animal food, the secretions require a less complicated apparatus for digestion than herb-eating quadrupeds; they possess greater strength and activity, and disclose, jn examination, a higher range of sensitive and intellectual faculties. Thus, there is a greater expansion of the brain, the senses have a superior acuteness, and the muscular power is enormous. The trunk of the body is lighter than that of vegetable feeders, especially in the abdominal region, and is compressed laterally; the spine is more pliant and elastic; the limbs have greater freedom of motion; the extremities are more subdivided, and they are armed with formidable weapons of offence and destruction.

Great mechanical power was required for raising the head, not only on account of the force to be exerted in tearing flesh, but also that these animals might be enabled to carry off their prey in their

"Carnivora.

mouths. Hence, we find that in the lion, the first vertebra of the neck has very widely-expanded transverse processes, while the second vertebra has a largely-developed spinous one, to supply levers for the muscles which have to perform these and other actions in which the head is concerned.

The teeth of this order are always of three kinds: incisors, or cutting teeth; canines, or canine teeth (so called from being particularly conspicuous in dogs); and molars, or grinders. The incisors are generally small and feeble, while the molars are modified in form according to the predominating quality of the food, and the canine teeth are strong, firm, and well developed.

The apparatus for giving motion to the jaws is likewise varied, according to the particular movements required by the different tribes to act upon the food. The articulation of the lower jaw with the temporal bone of the skull approaches to a hinge-joint; but considerable latitude is allowed to its

motions by the interposition of a movable cartilage between the two surfaces of articulation, which perfectly answers the intended purpose. Hence, in addition to the principal movements of opening and shutting, which are made vertically, the lower jaw has also some degree of mobility in a horizontal or lateral direction, and is likewise capable of being moved backwards or forwards to a certain

extent

The whole of the remaining part of the skeleton of these animals is constructed with reference

to their predatory nature. The sudden springs with which they pounce on their prey must violently shake the entire osseous frame. The first stroke with which they attempt the destruction of their victims is given with the fore leg; so that, had the limbs been rigidly connected with the breast-bone by means of an entire clavicle, its motions would have been too limited, and the danger of fracture would have been incurred. The scapula is therefore broad, and the fore leg of great length, compared with the same bones in ruminating animals; and the latter has, besides, a large surface for its

articulation with the scapula-thus allowing of a great range of motion. The radius and ulna are perfectly distinct, and play extensively on each other.

The fore feet rest on the ground by means of the second of the three joints, of which each toe is composed. The last joints are raised at right angles to the former, for the purpose of supporting the claws in an erect position. So important is it that these formidable instruments should constantly be kept sharp, and in a condition fit for immediate use, that there is an express contrivance for this purpose. It consists of a sheath, within which the claws, when not employed, are retracted, by means of an elastic ligament, which constantly tends to withdraw them within the sheath; and they are, at the

same time, so connected with the tendons of the flexor muscles of the toes, that the moment these muscles are thrown into action-which is the case when the animal aims a stroke with its paw-the claws are instantly drawn out, and combine in inflicting the severest lacerations.

HUMERUS OF BEAR.

Connected with the superior strength of the hind extremities, the pelvis extends further backwards, and more in a parallel line with the femur, or thigh-bone. This latter bone is longer and more slender than in the horse; but it is more compact in its form, and its processes are more strongly developed. The fibula, or hind leg, is a separate bone from the tibia, or leg.

The muscles, in general, are more divided into portions, and are thus capable of greater diversity of action, at the same time that they have greater power than those of herb-eating quadrupeds. The