Annulate lamellae in the pineal organ of a tinamid bird.

This study reports the occurrence of annulate lamellae in the rudimentary photoreceptor cells of the pineal organ of a tinamid bird Crypturellus parvirostris. The annulate lamellae observed in these cells are located in the cell body and are comprised of 1 to 8 parallel lamellae, symmetrically aligned and regularly spaced. Each lamella consists of pairs of parallel membranes interrupted by regularly spaced pores or annuli. These observations are discussed and compared with the structure and distribution of these organelles referred in the literature.