Abstract
1. The neural influence on the rate of regeneration of a limb in Asellus emanates from the segmental ganglion. It is independent of other centres of the c.n.s. 2. Operations on the animal cause a non-specific retardation of all limbs regenerating immediately afterwards. The immediate cause is probably haemorrhage, since the effect is both systemic and proportional to the severity of injury. 3. This general retardation acts differentially on a series of limbs, in proportion to their normal regeneration-rates. It has been possible to obtain a quantitative measure of this ‘differential inhibition’.