Fig. 10. Mean tenacity (A) and corrected tenacity (B) (± S.D., N=30) of the tube feet of the sea urchin Paracentrotus lividus (black bars) and the sea star Asterias rubens (grey bars), using a separation speed of 15 mm min^-1. Significant intraspecific differences between means for each type of substrata are indicated by letters in superscripts; means sharing the same letter are not significantly different (P 0.05, t-test).