The crab-eating opossum is a curious creature, about ten inches in length; with a prehensile tail, fifteen inches long, in addition. It has a somewhat pointed nose, and a darkish fur. When born, the young are transferred by the mother to her cradle pouch, where they live for some weeks before they are sufficiently developed to venture abroad. The creature is formed especially for living among the trees, about which it moves with the activity of a monkey. It advances carefully, always entwining its tail round one branch before venturing on to another. The crabs and other crustaceans on which it lives--from which circumstance it obtains its name--are found on low marshy soils, in the neighbourhood of which these species exist. MERIAN'S OPOSSUM. A still more curious creature is Merian's opossum (Philander dorsigerus). It has no true pouch, and the mother, therefore, while her young are in their infancy, carries them on her back. From this circumstance the name of _dorsigerus_, or back-bearing, has been given to it. They cling to her fur with their little hand-like feet, while they twine their tails round hers, which she places over her back in a convenient position for that purpose. Other species of opossums carry their young in the same manner,--some even which are furnished with well-developed pouches. YAPOCK OPOSSUM. The little yapock opossum is a representative of the aquatic species (Cheironectes yapock). It is of a fawn-grey tint, with dark black marks. It measures in length about ten inches, with a tail of twelve or fifteen inches. The hind-feet are furnished with a membraneous web, which connects the toes together, and serves as a paddle. The fore-paws possess great grasping powers, and have a hand-like appearance. The ears are small, sharp, and pointed, and the head tapering. It possesses also large cheek-pouches, similar in their use to those of monkeys. It is thus enabled to stow away the creatures it catches on its aquatic excursions, and to keep them there till it returns to the shore to dine. It feeds principally on fish, crustaceans, and aquatic insects. So similar is it in its habits to the otter, that it is frequently described as one, and has been called the Demerara otter; but it is in reality a true opossum. BATS. No animal's physiognomy can be more hideous, when seen from the front, than the countenance of the largest South American vampire-bat. Fancy a creature measuring twenty-eight inches in expanse of wing, its large leathery ears standing out from the sides and top of the head, and an erect spur-shaped appendage on the tip of the nose,--the grin, and the glistening black eye, all combining to make up a figure which reminds one of some mocking imp of fable. No wonder that imaginative people have conferred diabolical instincts on so ugly an animal.