Calcite c-axis orientation in ocular and genital plates of 88 species (mostly Recent regulars) shows a strong tendency to bilateral symmetry not corresponding to other symmetry of the adult test. The plane of bilateral symmetry apparently is fixed in the echinus rudiment before metamorphosis; species lacking a true larval stage also lack this symmetry. Apical system crystallography is more variable (generally at the family level) than that of other parts of the skeleton, but nevertheless can be used as an independent phylogenetic character. There is essentially no correspondence between apical system crystal orientations and those of ambulacral and interambulacral plates. The function of crystallographic patterns in the apical system may be navigational.