The Effect of Cytochalasin B Upon Tail Resorption and Metamorphosis in Ten Species Of

Cytochalasin B reversibly inhibits tail resorption and disrupts the organization of arrays of cytoplasmic filaments in the contractile cells. The effects of cytochalasin B on tail resorption and metamorphosis has been examined in ten species of ascidians, including representatives of 8 different families and 3 suborders. There is a considerable variation in the effective concentration of the drug when it is used with different groups of ascidians, and within a single species, discrete morphogenetic events characteristic of metamorphosis are differentially affected. The effective range of concentration of cytochalasin B which prevents tail resorption exhibited a striking phylogenetic correlation.