The vertical organization and spatial variation of the main features of the retina of juvenile loggerhead sea turtles (Caretta caretta) were studied. Eyes were sectioned into 5-μm slices and examined using light microscopy techniques. Within each section, photoreceptor cells and ganglion cells were identified and counted. The topographical organization of cells along the retina was examined for the presence of an area centralis. The results show that the basic organization of the loggerhead retina closely follows the general vertebrate model. The retina is duplex in nature, containing both cone and rod cells throughout the photoreceptor layer. Moreover, the organization of the neural layers indicates that this eye is adapted for both high spatial resolution and low light sensitivity. A higher concentration of both cone photoreceptor cells and ganglion cells occurs dorsal to the equator of the eye, and their numbers are positively correlated. These findings suggest that loggerhead sea turtles possess a horizontal streak in the dorsal region of the retina, an attribute that could be beneficial for the loggerhead's benthic lifestyle.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 2001 • No. 3