On the structure of retina of a fresh-water mullet, Rhinomugil corsula (Mugilidae, Pisces).

1. The structure of the eye-ball of Rhimomugil corsula has been described. 2. A mid-horizontal ridge (band) along the vitreal surface of the retina in each eye of R. corsula has been observed which divides the retina into a superior and an inferior hemispheres probably adapted for aquatic (dim-light vision) and aerial (bright-light vision) vision. 3. The superior hemisphere has been provided with poorly developed choroid gland and scarce pigment in the pigment epithelial cells. 4. The visual cell layer in the retina of the superior hemisphere contains both single and twin cones. They are alternately arranged in parallel rows. 5. The external and internal limiting membranes have been observed in both the hemispheres under light microscope. 6. The outer plexiform layer of the superior hemisphere contains many horizontal cells arranged into four distinct rows. 7. The inferior hemisphere has a well developed choroid gland, and dense pigment in the pigment epithelial cells.