Reticulum: a net-work; as of a cell.

Retina: that portion of the eye upon which the image is formed.

Retinaculum: in Lepidoptera, the loop into which the frenulum of the male is fitted; = hamus, q.v.: in Hymenoptera, horny, movable scales serving to move the sting or to prevent its being darted out too far: in Coleoptera, the middle, tooth-like process of the larval mandible.

Retinal pigment: the pigment layer of the compound eye just above the basilar or fenestrate membrane.

Retinophora: = retinula; q.v.

Retinula -ae: the retina of a single ocellus: the nerve fibres or cells between pigment cells and retina of the compound eye.

Retracted: drawn back; opposed to prominent.

Retractile: capable of being drawn in or retracted.

Retractor: used in drawing in or back; as a muscle.

Retroarcuate: curved backwards.