Fig. 4

Colony growth of Penetrantia clionoides within 26 days. In its growth, the principal stolon either produces further autozooids or pairs of additional stolons in regular intervals on its lateral sides. A Beginning of growth experiment. Asterisk marks the length of principal stolon at the beginning of growth experiment. B Stolon extension within week one. C First bud emerges. D Stolon extension within week two and lateral stolon branch emerges. E Second bud emerges. F Stolon extension within week three. G Final size of colony which is reconstructed in Fig. 5. Abbreviations ast – additional stolon, b1 – bud1; b2 – bud2, b3 – bud3, bha – borehole apertures, pst – principal stolon, tu – tubulet