One of the single eyes forming the compound eyes of crustaceans, insects, and other invertebrates; one of the eyes of an ommateum.
Gr. omma: an eye] • One of the units which, collected into groups of up to 20,000, make up the compound eye of arthropods.
Plural: ommatidia. A a cylinder-shaped unit of a compound eye. Each ommatidium receives light from a narrow part of an animal's field of view and acts like a separate eye. An ommatidium has its own facet, crystalline cone (lens), light receptors (retinulae), and optic nerve fiber.
each single photoreceptive element of the compound eye.
(pl., ommatidia) Single sensory cell of a compound eye (see also facet). [drawing][photo
Discrete optical unit of the insect compound eye, with a lense focusing light from a small angle of the visual field onto a small group of photoreceptors
a facet of the sessile subintegumentary compound eye
any of the numerous small cone-shaped eyes that make up the compound eyes of some arthropods
(pl. ommatidia) one division of compound eye
One of the structural elements, resembling a single simplified eye, that make up the compound eye of insects and other arthropods.
(plural omnitidia) The ommatidia are the parts of an insect's compound eye which receive light from a small part of the insect's field of vision. Each ommatidium is a cylindrical unit composed of a hexagonal lens-cornea and crystalline cone (which receive the light and focus it) plus a rhabdome (which is stimulated by light and sends signals to the optic nerve to the brain).
The compound eye of insects is composed of hundreds of units called ommatidia. An ommatidium contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The outer part of the ommatidium is overlaid with a transparent cornea.
