Richard Lydekker

“ The second sub-genus, or genus, Metachirus contains a considerable number of species found all over the tropical parts of the New World. They are of medium size, with short, close fur, very long, scaly and naked tails, and have less developed ridges on their skulls. They have, as a rule, no pouch in which to carry their young, and the latter therefore commonly ride on their mother's back, holding on by winding their prehensile tails round hers, as in the figure of the woolly opossum. ”

“ Opossums are small animals, varying from the size of a mouse to that of a large cat, with long noses, ears and tails, the latter being as a rule naked and prehensile, and with the first toe in the hind-foot so fully opposable to the other digits as to constitute a functionally perfect posterior “hand.” These opposable first toes are without nail or claw, but their tips are expanded into broad flat pads, which are of great use to these climbing animals. ”

“ On the anterior limbs all the five digits are provided with long sharp claws, and the first toe is but little opposable. The numerous cheek-teeth are crowned with minute sharply-pointed cusps, with which to crush the insects on which these creatures feed, for the opossums seem to take in South America the place in the economy of nature filled in other countries by hedgehogs, moles, shrews, &c. The true opossums are typically represented by Didelphys marsupialis, a species, with several local races, ranging over the greater part of North America (except the extreme north) . ”