• Our story about email software that reminds you to send an attachment (29 July, p 25) failed to note that KMail, Spamnix and Pegasus Mail already have this facility.
• We said that the mammalian super-order Pegasoferae contains horses, cats and dogs, cows, whales and hedgehogs (24 June, p 23). In fact, cows and hedgehogs are not members of this super-order.
• Gravity has a negligible effect on the behaviour of ink drops at the micro-scale shown in our “Second sight” photograph (19 August, p 46). Surface tension and liquid viscosity are the only relevant forces.
