Description: English: Alder J. & Hancock A. (1845-1855). A monograph of the British nudibranchiate Mollusca: with figures of all the species. The Ray Society, London. Published in 8 parts:Part 5 Fam.1 Plate 22 [1851]. Polycera quadrilineata (O. F. Müller, 1776). Date: 1851. Source: https://www.biodiversitylibrary.org/item/131598#page/200/mode/1up. Author: Albany Hancock.