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358 MEGALOPOLIS MEGALOSAURUS form diameter, with the crown hollowed in the middle, and projecting border ; as in other eden- tates, they are deeply excavated from the bot- tom for the persistent dental pulp ; they have no enamel, being composed of very porous, dentine in the centre, surrounded by a harder layer of the same which is enclosed by a thin- ner crust of cementurn ; the formula is if , the anterior tooth being considerably in advance of the others, in form and position like a canine ; the'y vary in diameter from 8 lines to an inch ; the rarai of the lower jaw are widely separated, and the symphysis narrow. The bones of the skeleton are strong, though less so than in the allied megatherium; the scapula is about 1 ft. long, the humerus 20 in. ; the thigh bones are relatively shorter and broader than in the sloths and about 21 in. long ; the tibiae rela- tively very much shorter than in the sloths, but of greater relative length than in the mylodon ; the shaft of the humerus suddenly expands toward the lower extremity, and is pierced by a large foramen; the astragalus like that of recent sloths, 5 by 3f in. ; the heel bone developed in an extraordinary manner, being long, compressed, and high; the phalanges large and narrow, and armed with powerful claws; the tibia and fibula distinct, and the foot articulated obliquely, the last leading Mr. Lund to the opinion that the animal was a climber ; the anterior limbs a little longer than the posterior ; the tail strong and solid. From the study of the toes Cuvier pronounced the animal an edentate ; the well marked ridge in the middle of the articulating surface of the last phalanx indicates a more restricted motion than in carnivora, to which Mr. Jefferson re- ferred it ; the upper edge extends further back than the lower, preventing the claws from be- ing raised above a horizontal line, but permit- ting complete flexion below, as in sloths ; their form and proportions are also those of eden- tates ; the middle and third fingers are large, with very strong claws, the index being smaller with a less strong claw, and the thumb and little finger rudimentary. This animal was less heavy 'in form than the megatherium, which it doubtless resembled in its habits; it was probably of the size of a large ox. The bones are found in the pleistocene or drift for- mations of America, contemporaneous with the elephant and mastodon, and perhaps surviving them ; bones of another species are found in Brazil. (See MEGATHERIUM.) MEGALOPOLIS, a city of ancient Greece, ori- ginally capital of the Arcadian confederation, on the river Helisson. It was founded at the suggestion of Epaminondas, after the battle of Leuctra (371 B. 0.), and was designed by him as a check to Sparta. Forty townships fur- nished inhabitants for the new city, which was m. in circumference, and had a larger domain allotted to it than that possessed by any Ar- cadian state. But it never attained the im- portance anticipated for it, and was too large for its population, that of its entire territory being but 65,000. Apprehension of Sparta afterward drove the Megalopolitans into alli- ance with the Macedonians, and held them aloof from the coalition formed in Greece on the death of Alexander for the recovery of inde- pendence. They at length fell under the do- minion of tyrants, the last of whom, Lydiades, resigned in 234, and united Megalopolis to the Achaean league. In 222 Cleomenes III., king of Sparta, captured it by surprise, and de- stroyed the greater part of it ; but after his de- feat at the battle of Sellasia (221) the Megalo- politans who had fled returned under the con- duct of Philopcemen, and rebuilt the city on the original scale; but it never regained its former prosperity, and rapidly sank into insig- nificance. It contained no acropolis, owing to its flat situation, but a magnificent agora, colos- sal statues, and famous temples. Little re- mains of this great city, which used to be called the great desert, owing to its magnificent dis- tances, excepting the well preserved ruins of the theatre, which Pausanias regarded as the largest in Greece; and they are still visible amid the thickets and corn fields which cover the site of the city near the village of Sinano. MEGALOSAURUS (Gr. piyas, great, and aavpos, lizard), a gigantic fossil reptile of the family of dinosaurians, which includes the iguanodon, previously described. This family, entirely ex- tinct, was remarkable for great size and for certain mammalian characters ; the long bones have a medullary cavity, the feet are short and pachyderm-like, the sacrum composed of at least five anchylosed vertebra, the ribs doubly articulated to the spine, the vertebral laminas greatly developed, and the lower jaw capable of a horizontal triturating motion; but the Megalosaurus (restored). teeth, scapular arch, and most of the skeleton resemble those of lizards. The genus megalo' saurm (Buckland) was discovered by Dr. Buck- land in the Stonesfield oolite near Oxford, Eng. ; remains have also been found in the Wealden and Jurassic formations. The M. Bucklandi