Page:EB1911 - Volume 17.djvu/797

 soles. A pouch is present, and there are eight or ten teats. Nearly allied is the jumping Antechinomys laniger, of East Central Australia, an elegant mouse-like creature, with large oval ears, elongated limbs, a long and tufted tail and no first hind toe. In connexion with the large size of the ears is the excessive inflation of the auditory bulla of the skull.

From all other members of the family the marsupial, or banded, ant-eater (Myrmecobius fasciatus) differs by the presence of more than seven pairs of cheek-teeth in each jaw, as well as by the exceedingly long and protrusile tongue. Hence it is made the type of a distinct sub-family, the Myrmecobiinae, as distinct from the Dasyurinae, which includes all the other members of the family. From the number of its cheek-teeth, the banded ant-eater has been regarded as related to some of the primitive Jurassic mammals; but this view is disputed by Mr Bensley, who regards this multiplicity of teeth as a degenerate feature. On the other hand, it is noteworthy that this marsupial retains in its lower jaw the so-called mylo-hyoid groove, which is found in the aforesaid Jurassic mammals. Myrmecobius has a total of 52 or 54 teeth, which may be classed as i., c. , p. + m. . The teeth are all small and (except the four posterior inferior molars) separated from each other by an interval. Head elongated, but broad behind; muzzle long and pointed; ears of moderate size, ovate and rather pointed. Fore-feet with five toes, all having strong pointed, compressed claws, the second, third and fourth nearly equal, the fifth somewhat and the first considerably shorter. Hind-feet with no trace of first toe externally, but the metatarsal bone is present. Tail long, clothed with long hairs. Fur rather harsh and bristly. Female without pouch, the young when attached to the nipples being concealed by the long hair of the abdomen. Vertebrae: C. 7, D. 13, L. 6, S. 3, Ca. 23. The single species, which is a native of western and southern Australia, is about the size of an English squirrel, to which its long bushy tail gives it some resemblance; but it lives entirely on the ground, especially in sterile sandy districts, feeding on ants. Its prevailing colour is chestnut-red, but the hinder part of the back is marked with broad, white, transverse bands on a dark ground.

With the bandicoots, or Peramelidae, we come to a family of polyprotodonts which resemble the diprotodonts in the peculiarly specialized structure of their hind limbs; an adaptation which we must apparently regard as having been independently acquired in the two groups. The dentition is i., c. , p. , m. ; total, 48; the upper incisors being small, with short, broad crowns; the lower incisors moderate, narrow, proclivous; canines well developed. Premolars compressed, pointed; and the molars with quadrate tuberculated crowns. Deciduous premolar preceded by a minute molariform tooth, which remains in place until the animal is nearly full grown. Fore feet with two or three of the middle toes of nearly equal size, and provided with strong, sharp, slightly curved claws, the other toes rudimentary. Hind feet long and narrow; the first toe rudimentary or absent; the second and third very slender and united in a common integument; the fourth very large, with a stout elongated conical claw; the fifth smaller than the fourth (see fig. 6). The terminal phalanges of the large toes of both feet cleft at their extremities. Head elongated, with the muzzle long, narrow and pointed. Stomach simple. Caecum of moderate size. Pouch complete, generally opening backwards. Alone among marsupials bandicoots have no clavicles. More remarkable still is the development of a small allantoic placenta.

In the true bandicoots of the genus Perameles (fig. 5) the fore-feet have the three middle toes well developed, the third slightly larger than the second, the fourth somewhat shorter, provided with long, strong, slightly curved, pointed claws. First and fifth toes very short and without claws. Hind feet with one or two phalanges, in the first toe forming a distinct tubercle visible externally; the second and third toes very slender, of equal length, joined as far as the terminal phalange, but with distinct claws; the fifth intermediate in length between these and the largely developed fourth toe. Ears of moderate or small size, ovate, pointed. Tail rather short, clothed with short depressed hairs. Fur short and harsh. Pouch opening backwards. Vertebrae: C. 7, D. 13, L. 6, S. 1, Ca. 17. (see .)

The rabbit-bandicoot, Peragale (or Thylacomys) represents a genus in which the cheek-teeth are curved, with longer crowns and shorter roots than in the last. Hind extremities proportionally longer with inner toe represented only by a small metatarsal bone. Muzzle much elongated and narrow. Fur soft and silky. Ears very large, long and pointed. Tail long, its apical half-clothed on the dorsal surface with long hairs. Pouch opening forwards. Vertebrae: C. 7, D. 13, L. 6, S. 2, Ca. 23.

The one species, from Western Australia, is the largest member of the family, being about the size of a rabbit, to which it bears sufficient superficial resemblance to have acquired the name of “native rabbit” from the colonists. It burrows in the ground, but in other respects resembles bandicoots in habits.

In the pig-footed bandicoot (Choeropus castanotis) the dentition generally resembles that of Perameles, but the canines are less developed, and in the upper jaw two-rooted. Limbs very slender; posterior nearly twice the length of the anterior. Fore feet with the functional toes reduced to two, the second and third, of equal length, with closely united metacarpals and short, sharp, slightly curved, compressed claws. First toe represented by a minute rudiment of a metacarpal bone; the fourth by a metacarpal and two small phalanges without a claw, and not reaching the middle of the metacarpal of the third; fifth entirely absent. Hind foot long and narrow, mainly composed of the strongly developed fourth toe, terminating in a conical pointed nail, with a strong pad behind it; the first toe represented by a rudimentary metatarsal; the remaining toes completely developed, with claws, but exceedingly slender; the united second and third reaching a little way beyond the metatarso-phalangeal articulation of the fourth; the fifth somewhat shorter. Tail not quite so long as the body, and covered with short hairs. Ears large and pointed, and folded down when the animal is at rest. Fur soft and loose. Pouch opening backwards. Vertebrae: C. 7, D. 13, L. 6, S. 1, Ca. 20.

The only species of this genus is about the size of a small rat, found in the interior of Australia. Its general habits and food appear to resemble those of other bandicoots. A separate family, Notoryctidae, is represented by the marsupial mole (Notoryctes typhlops), of the deserts of south Central Australia, a silky, golden-haired, burrowing creature, with a curious leathery muzzle, and a short, naked stumpy tail. The limbs are five-toed, with the third and fourth toes of the front pair armed with enormous digging claws;