A little armadillo, the mulita, is the living representative of the antediluvian giants Mylodon, Megatherium, &c. The ostrich-Rhea americana-roams everywhere in the plains; and there are a few specimens of the vulture tribe, a native crow (lean, tall and ruffed), partridges and quails.
Of the Pleistocene and recent deposits the most interesting are the remains of extinct animals (Glyptodon, Mylodon, Megatherium, &c.) in the caves of the Sao Francisco.
MEGATHERIUM (properly Megalotherium), a huge extinct edentate mammal from the Pleistocene deposits of Buenos Aires, typifying the family Megatheriidae (or Megalotheriidae), and by far the largest representative of the Edentata.
Except, indeed, for its relatively shorter limbs Megatherium americanum rivalled an elephant in bulk, the total length of the skeleton being 18 feet, five of which are taken up by the tail.
The Megatheriidae, which include a number of genera, are collectively Megatherium, from the specimen in the Museum of the Royal College of Surgeons of England.
From all these Megatherium differs in the form and structure of the teeth.
Unlike sloths, the megatherium has seven cervical vertebrae; and the spines of all the trunk-vertebrae incline backwards.
Although similar teeth occur in the phosphorite beds of South Carolina, which may have been transported from elsewhere, no undoubted remains of Megatherium are known from North America.
For certain small ground-sloths from Patagonia with Megatherium- like teeth, see MYLODON.
From Megatherium these animals, which rivalled the Indian rhinoceros in bulk, differ in the shape of their cheek-teeth; these (five above and four below) being much smaller, with an ovate section, and a cupped instead of a ridged crown-surface, thus resembling those of the true sloths.
The skull is shorter and lower than in Megatherium, without any vertical expansion of the middle of the lower jaw, and the teeth also extend nearly to the front of the jaws; both these features being sloth-like.
In the fore feet the three inner toes have large claws, while the two outer ones are rudimentary and clawless; in the hind-limbs the first toe is wanting, as in Megatherium, but the second and third are clawed.
Megatherium and B.
All the above genera differ from Megatherium in having a foramen on the inner side of the lower end of the humerus.