定義： Capable of creating a new organism by combining the genetic material of two gametes, which may come from two parent organisms or from a single organism, in the case of self-fertilizing hermaphrodites.
定義： Repeated, thickened, raised structures on the shell or carapace surface, comparable to or greater than the thickness of the shell/carapace and covering a notable portion of it. Thickenings can be either radial, comarginal, axial or spiral.
定義： Plications, undulations or other folds on the shell or carapace surface, less than the thickness of the shell/carapace and covering a small area of it, with thickness remaining consistent across folds.
定義： Museum National d'Histoire Naturelle (MNHN), Paris, France. URL for main institutional website: http://www.mnhn.fr/museum/foffice/science/science/sommaire.xsp
定義： A compound eye with no separation between the crystalline-cone layer and the retinula, each rhabdom receiving light only from its own corneal lens.
定義： 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.
