This research describes the pineal complex histology in juvenile and adult Cichlasoma dimerus , and the effect of different photoperiods on its cell morphology. In both juveniles and adults, the pineal complex of C . dimerus has three components: the pineal organ, consisting of a pineal vesicle ( PV ) and a pineal stalk, the parapineal organ and the dorsal sac. Although a strong morphological resemblance exists between the two...