This family consists of the pedibin and Hym-346 signalling peptides. These two peptides have been isolated from Hydra vulgaris and Hydra magnipapillata. Experiments have indicated that both cause a reduction in the positional value gradient, the principle patterning process governing the maintenance of form in the adult hydra. The peptides cause an increase in the rate of foot regeneration following bisection of the body column. Thus both play important signalling roles in patterning processes in cnidaria and maybe in more complex metazoans.