Colossal statues of ivory continued in favor under the Romans, and Phidias had many followers: thus Adrian had completed the temple of Jupiter at Athens; he erected in it a large statue of gold and ivory. These grand works fell into disuse when Christianity was established under Constantine, and probably many of these works of art were destroyed at this time. All that remain of the vast numbers of ivory statues is a figure about eight inches in height, and the works referred to on previous pages. At the present day, ivory sculpture is confined to small figures of various kinds, the most extensive work being done by the Chinese and Japanese artists: the latter delight in the grotesque productions of their art. According to the Davenport Academy of Sciences, to which I am indebted for permission to use the accompanying engravings, the mastodon figured in the arts of the mound-builders. The pipes shown in Plate XVIII. presumably represent a proboscidian; and many notable archæologists believe that the pipe-makers were familiar with the mastodon, and perpetuated its form in the pipes. According to Mr. Charles E. Putnam, president of the Academy, one of the pipes was found, in 1880, in a mound on the farm of Mr. P. Hass, in Louisa County, Io., the discoverer being the Rev. A. Blumer, a Lutheran clergyman, who presented the pipe to the Academy. The other pipe was obtained by Rev. J. Goss from a farmer in the same county, who found it while planting corn on his farm some time previous. The famous big elephant mound in Grant County, Wis., is supposed to represent an elephant in profile, the huge, pillar-like legs and the trunk being plainly seen; though it might well have been intended to represent any other animal of like shape. CHAPTER XX. ELEPHANTS IN THE AMPHITHEATRE. As the elephant was used in the early days to add to the pomp and glory of the Roman conquerors, it is not surprising that they were also employed in the games and sports of the people. It was the custom in the days of old Rome, to match men against the most ferocious animals; and, long before the elephant was known in Italy, brave men met the lion, single-handed, in the arena. When the elephant was introduced, it was evident that the amphitheatre had new possibilities; and forthwith the huge animals became a feature of the barbaric pastimes of the period. It is needless to say that a people given to such diversions, which involved the torture of thousands of living creatures, were grossly debased morally. Milton has thus described the times and men under Tiberius:—