Definition: A taxon is Vulnerable when the best available evidence indicates that it meets any of the criteria A to E for Vulnerable, and it is therefore considered to be facing a high risk of extinction in the wild.
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
