الفهرس 
Chapter IOnly 14 pages are availabe for public view
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Abstract
The study aimed to describe the histological development of the inner layer of the eye ”the retina” in the gilt-head seabream Sparus aurata. The retinal pigment epithelium (RPE) is the pigmented cell layer just outside the neurosensory retina. The neural retina is formed by layers of neurons and glia. The light-sensitive portions (the outer segments) of the photoreceptors (the rods and cones) are located in the receptor layer that lies adjacent to the retinal pigment epithelium. The cell bodies of retinal neurons form the darkly stained retinal layers: the outer nuclear layer, the inner nuclear layer and the ganglion cell layer. Between the outer and inner nuclear layer are the outer plexiform layer and the inner plexiform layer. Interior to the ganglion cell layer, the axons of the retinal ganglion cells form the optic nerve fiber layer in their course to the optic disc. These axons exit the eye at the disc and form the optic nerve, cranial nerve II. The present study revealed that the gilthead seabream is an altricial sparid teleost that hatches with undifferentiated retina, the development of the retina closely correlated with the complete consumption of yolk, and the histogenesis of the retina takes place during the late prolarval and early larval stages. The structure of the larval retina shows adaptation with the mode of life (light vision) since it possesses a relatively large number of cones. On the contrary, the benthopelagic adults exhibit rod-dominated retina to adapt to the night vision. Consequently, it’s concluding that altricial benthic fishes as Sparus aurata form as an informative experimental model to determine the correlation between the morphological development of the retina and vision at the dim-light condition.