NOTICE OF THE MEGATHERIUM. 
7 
taining of this massive protecting shield. He sums up in favor of the opinion that the 
Megatherium had the habits and manners of the Armadillos, and consequently it fed upon 
flesh, and perhaps also upon roots ; and that it was wont to dig the earth with its enormous 
claws, if not for concealment, at least for tearing open the nests of ants. Dr. Lund, of 
Copenhagen, was more bold than all others in his conjectures, and held unreservedly the 
opinion that the Megatherium climbed trees like Sloths at the present day, — the vegetation 
of that primeval age being on the same magnificent scale with the animal creation. 
The merit of clearing up the mist which hung over the nature and structure of this 
most remarkable of all fossil mammals, was reserved for Professor Owen, the accomplished 
English zoologist and comparative anatomist, the worthy successor of the peerless Cuvier* 
His “Memoir on the Megatherium,” published in 1860, throws a flood of light on the habits 
and natural affinities of this singular quadruped. The following sketch, based upon that 
Memoir, will contain the main results of his investigation, together with such other points of 
interest as suggest themselves. He conclusively proves that the Megatherium was a ground 
Sloth, feeding on the foliage of trees, which it uprooted by its great strength ; that it was 
not a burrower ; and that it did not wear a bony armor. 
§ 2. ANATOMICAL STRUCTURE. 
The Head of the Megatherium presents the form of an elongated parallelogram, and is 
chiefly characterized by its small relative size, by the great depth of the lower jaw, and by 
the extraordinary size of the processes ascending and descending from the zygomatic arch. 
The length of the skull is thirty-one inches; of the lower jaw, tweuty -seven. Breadth 
across the widest part of the zygomatic arches, eighteen inches. In front, the palatine and 
maxillary portions descend considerably below the level of the rest of the skull, giving to the 
upper line of the head a very precipitate forward slope. The skull is unusually cellular, and 
the innermost stronger plate is covered with an outer table and intermediate walls to resist the 
violent shocks to which the animal was exposed. The brain-cavity within is thus far smaller 
than might be expected from the size of the skull.* The occipital condyles are very promi- 
nent, and their articular surface is so prolonged on all sides as to indicate great freedom of 
* The unfavorable idea of the animal’s intelligence which is given by the very sloping head of the Mega- 
therium, is not warranted by that fact alone. Here, as in many others of the mammals, the bony air-cells 
interposed between the outer and inner plates of the skull, quite mask the size of the brain-cavity. The most 
remarkable development of these cells in the Mammalian class is presented by the Elephant, as it is by the 
Owl among birds ; the intellectual physiognomy of these animals being caused not by the actual capacity of the 
brain, but by the enormous extent of the cellular structure between the skull-walls. 
