| Abstract: | The elongation of stolon and the formation of an endoblastic vesicle leading to the differentiation of a blastozooid in an isolated stolon piece of Perophora orientalis were described. A treatment of isolated stolon pieces with 2 × 10?2 M thiourea for 5 hr completely inhibited stolon elongation and at the same time accelerated the formation of an endoblastic vesicle. Inversely, 10?5 M thyroxine and 10?5 M triiodothyronine markedly stimulated stolon elongation with concomitant suppression of the formation of an endoblastic vesicle. The isolated stolon piece was thus proved to be experimentally directed either to the elongation of stolon or to the formation of an endoblastic vesicle, and to be a potential system for the study of the control mechanisms between the two alternative pathways, growth and differentiation. |
