Perikymata are the external surface manifestations of: (A) Enamel rods, (B) Incremental lines of retzius, (C) Nasmyth's membrane, (D) Pellicle
Answer is B. The number of perikymata gradually decreases form cervical region to occlusal or incisal region because of undisturbed development of enamel prior to birth. Perikymata are usually absent in prenatally developed occlusal parts of deciduous teeth, whereas they are present in postnatal cervical parts.