A compound eye is a visual organ found in arthropods such as insects and crustaceans.
Crustaceans (Crustacea) form a large, diverse arthropod taxon which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill, woodlice, and barnacles.
Insects or Insecta (from Latin insectum) are hexapod invertebrates and the largest group within the arthropod phylum.
Invertebrates are animals that neither possess nor develop a vertebral column (commonly known as a backbone or spine), derived from the notochord.
Journal of Comparative Physiology was a journal that split into Journal of Comparative Physiology A and Journal of Comparative Physiology B in 1984.
The compound eyes of arthropods like insects, crustaceans and millipedes are composed of units called ommatidia (singular: ommatidium).
An optical axis is a line along which there is some degree of rotational symmetry in an optical system such as a camera lens or microscope.
The Portable Document Format (PDF) is a file format developed in the 1990s to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems.
In optics a ray is an idealized model of light, obtained by choosing a line that is perpendicular to the wavefronts of the actual light, and that points in the direction of energy flow.
The Journal of Experimental Biology is a peer-reviewed scientific journal in the field of comparative physiology and integrative biology.