HETEROCHRONY: THE EVOLUTION OF ONTOGENY, by M.L. McKinney and K.J. McNamara. Plenum Press, New York and London, 437 pp. EVOLUTIONARY TRENDS, edited by K.J. McNamara, Bellhaven Press, 1990, xviii+368 pp. illust. ISBN 1-85293-091-8. Price £45. OSTRACODA AND GLOBAL EVENTS, edited by R.C. Whatley and C. Maybury, Chapman and Hall. ISBN 0-412-36300-3. xviii+621 pages. £65 Hardback.