Definition: A savanna biome is a woodland biome which has seasonal water availability and includes, across its entire spatial extent, trees spaced sufficiently far apart to allow an unbroken layer of grass, sedge (Cyperaceae) or rush (Juncaceae) communities to live.
Definition: A compound eye with no separation between the crystalline-cone layer and the retinula, each rhabdom receiving light only from its own corneal lens.
Definition: Eye-spots which may be set into a pit to reduce the angles of light that enters, to allow the organism to deduce the angle of incoming light. Lens-like structures may be present, but stemmata, unlike lens eyes, cannot form an image, either for lack of refractive power or retinal resolution.
Definition: A light sensing organ composed of multiple ommatidia, visual units consisting of a limited number of rhabdomeric photoreceptor cells, cornea-secreting epithelial cells, interommatidial pigment cells, and sometimes crystalline cone cells
Definition: A light sensing organ composed of multiple ommatidia, visual units consisting of a limited number of rhabdomeric photoreceptor cells, cornea-secreting epithelial cells, interommatidial pigment cells, and sometimes crystalline cone cells
