Another species is interesting from being found in the part of California which adjoins Mexico. The Short-headed Opossum also belongs to this group, and is from the same locality. Besides these, there are several smaller pouch-bearing Opossums, without the long hair of those just mentioned, and they are from Brazil, Guiana, and Surinam--for instance, the Quica, the Naked-tailed, and the Four Spotted kinds. The Philander Opossum is a bird-hunter, and lives in Surinam. The next group of Opossums have no pouch, but there may be folds of the skin protecting the mammæ. THE THICK-TAILED OPOSSUM.[126] As its name implies, this pouchless Opossum has a very thick tail. Moreover, it has smaller ears than the other Opossums, and has a short head and short legs. The fur is made up of harsh hairs, which are close to the body, and there is but little under fur. Its colour is yellow-brown, but the eye and muzzle are brownish, and the tail, with the terminal two-thirds, is black, with the exception of a small white spot at the end. It inhabits Brazil and Paraguay, and extends southwards to the River Plate. One of the Opossums was kept by D’Azara, who found it quiet, tame, and stupid; but having been fed on raw meat, and a parrot happening to come too close, it killed the bird in a moment. There are folds of skin in the lower part of the abdomen, but no pouch, and there are six mammæ. Another of the Opossums is called Merian’s Opossum, or _Didelphys dorsigera_, and it inhabits Surinam. It was described by Madame Merian in 1717, who represented it in her great book on insects with its young clustered on its back and hanging on to the mother’s tail, which was curved over its back, with their little tails. [Illustration: MERIAN’S OPOSSUM.] It is very curious that the young of these pouchless Opossums should resemble those of the whole order in being comparatively little advanced in their development at the time of their birth. The young are at first strongly attached to the teats of the mother, and when they are sufficiently strong and grown to leave them, occasionally she takes them off from the nipples and places them on her back. Here they cling on with their tails to hers. Hence the name of back-bearing, or Dorsigera, which is given to this kind. [Illustration: YAPOCK.] It was at first supposed that this method of carrying the young was restricted to this species, but subsequent experience has shown that several kinds do the same thing. Two or three other species of Opossum are interesting from their small size and habits. Thus the Murina Opossum (_Didelphys murina_), with a very long tail, inhabits Guiana, Brazil, Peru, and Mexico. The body is about five inches in length, and the tail is either slightly longer or about the same. Yet this little thing attacks birds and insects; it burrows in the ground, and climbs trees to get its insect food.