Abstract
The fine structure of ellipsoids in a number of vertebrate retinas was studied in material prepared with various fixatives. Several atypical ellipsoidal mitochondria were found in ellipsoids of certain animals. A peculiar configuration of the internal mitochondrial membranes caused by fusion of the outer surfaces of adjacent cristae teas found in the lamprey retina. Intramitochondrial glycogen granules and granular or filamentous intracristal inclusions were observed in the toad and giant salamander, respectively. In photoreceptor cells of the gecko, carp, and snake, the ellipsoid was particularly differentiated, containing modified mitochondria. The possible functional significance of such differentiated ellipsoids is discussed briefly with respect to the oil droplets.