FIG. 10. — Biometric data on Thylechinus (T.) sinaiensis n. sp. showing the relation between: test diameter and test height (H); test diameter and both of width of ambulacrum (Wa, filled quadrangles, solid line) and width of interambulacrum (Wi, empty quadrangles, dashed line); test diameter and each of number ambulacral tubercles per row (Na, filled quadrangles, solid line) and number of interambulacral tubercles per row (Ni, empty quadrangles, dashed line); test diameter and each of diameter of peristome (Dp, filled quadrangles, solid line) and length of apical system (Ls, empty quadrangles, dashed line).