in Architecture, an arched roof or ceiling, more especially the planking or flooring above porticos or piazzas.

LACYDES was born at Cyrene, a city on the northern coast of Africa. Of his personal history we are able to collect a few facts from Suidas and Diogenes Laertius. He was the son of a certain Alexander, of whom we know nothing except the name, and that his poverty exposed his son to many hardships. The love of learning drew Lacydes to Athens at the time when Arcesilaus had become the founder of what has been called the Middle Academy. He became the pupil of Arcesilaus, and by his acuteness and varied acquirements soon procured for himself the friendship of his instructor. On the death of Arcesilaus he succeeded to the vacant chair, b. c. 241, and presided in the academy for twenty-six years; at the end of which he abdicated, b. c. 215, in favour of two of his disciples, Evander and Telechus. Laertius asserts that he deserted the tenets of Arcesilaus; but Cicero (Acad. iv. 6) states that he continued to teach the same doctrines as his predecessor. He taught that there was no certainty in philosophical knowledge; and that in all purely speculative subjects we must refrain from coming to a decision, because the mind of man cannot sufficiently distinguish truth from falsehood. He does not, however, appear to have carried these sceptical opinions into the every-day affairs of life, but to have restricted them to philosophy and science; though his opponents asserted, and with much reason, that such doctrines as he advocated tended to undermine all virtue. Ladder and morality. Lacydes was the friend of Attalus king of Pergamus, and was invited by him to take up his residence at his court; but he answered, that philosophers admired the portraits of kings most at a distance. The latter part of his life was spent, if we can credit the statements handed down to us, very differently from his early years. He gave himself up to every kind of debauchery, and his passion for wine replaced the taste for study. Athenaeus (x. 10) states that he was the greatest wine-bibber of his age, and often came off victorious in contests of that kind. He at last died in consequence of one of his excesses.