size of the beasts. It possesses more mammals that are unique and distinctive in type than does any other continent save Australia; and they are of higher and much more varied types than in Australia. But there is nothing approaching the majesty, beauty, and swarming mass of the great mammalian life of Africa and, in a less degree, of tropical Asia; indeed, it does not even approach the similar mammalian life of North America and northern Eurasia, poor though this is compared with the seething vitality of tropical life in the Old World. During a geologically recent period, a period extending into that which saw man spread over the world in substantially the physical and cultural stage of many existing savages, South America possessed a varied and striking fauna of enormous beasts—sabre-tooth tigers, huge lions, mastodons, horses of many kinds, camel-like pachyderms, giant ground-sloths, mylodons the size of the rhinoceros, and many, many other strange and wonderful creatures. From some cause, concerning the nature of which we cannot at present even hazard a guess, this vast and giant fauna vanished completely, the tremendous catastrophe (the duration of which is unknown) not being consummated until within a few thousand or a few score thousand years. When the white man reached South America he found the same weak and impoverished mammalian fauna that exists practically unchanged to-day. Elsewhere civilized man has been even more destructive than his very destructive uncivilized brothers of the magnificent mammalian life of the wilderness; for ages he has been rooting out the higher forms of beast life in Europe, Asia, and North