retinula Biol.
(rɛˈtɪnjʊlə)
Pl. -ulæ. Also anglicized as retinule (ˈrɛtɪnjuːl).
[Diminutive, on L. types, of retina; coined in Ger. by H. Grenacher in Untersuchungen über das Arthropoden-Auge (1877) ii. 17.]
One of the pigmented cells from which, in certain compound eyes of Arthropods, the rhabdom arises. Also attrib. (appositively).
| 1878 Bell tr. Gegenbaur's Comp. Anat. 264 The retinal cells which give rise to the rhabdom constitute a retinula. 1883 Q. Jrnl. Microsc. Sci. XXIII. 186 What Grenacher has called, in the multicorneal eye of Insects and Crustaceans, a ‘retinula’. 1888 Rolleston & Jackson Anim. Life 168 A basement membrane..separates the retinulae from the optic ganglion. 1924 Glasgow Herald 31 May 4/2 The insect's compound eye..has its numerous lenses and retinules each wrapped up in a black mantle. 1978 Nature 29 June 772/1 The Drosophila compound eye consists of about 700 ommatidia, each containing six peripheral and two central retinula cells (photo⁓receptors). |
Hence reˈtinular a.; reˈtinulate a.
| 1883 Q. Jrnl. Microsc. Sci. XXIII. 211 Retinulate, of an ommateum in which the nerve-end cells are segregated to form definite groups, or ‘retinulæ’. 1888 Rolleston & Jackson Anim. Life 516 Scutigera has a retinulate ommateum. Ibid. 525 In Limulus the central eyes have groups of five retinular cells. |