Speusippus in Harpers Dictionary of Classical Antiquities (1898)

(Σπεύσιππος). An Athenian philosopher, son of Eurymedon and Potoné, a sister of Plato. He accompanied his uncle, Plato, on his third journey to Syracuse, where he displayed considerable ability and prudence. He succeeded Plato as president of the Academy, but was at the head of the School for only eight years (B.C. 347-339). He wrote several works, all of which are lost, in which he developed the doctrines of his great master.

Link: http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0062%3Aalphabetic+letter%3DS%3Aentry+group%3D16%3Aentry%3Dspeusippus-harpers