Polycera quadrilineata. Site: S of Ballyhenry Island,  Strangford Lough
 Polycera quadrilineata. Event number: 20200906/01. Site: S of Ballyhenry Island, Strangford Lough. 2020-09-06. Photograph © Bernard Picton. (18/22) 
 Bernard Picton (2026). Photograph of Polycera quadrilineata. Site: S of Ballyhenry Island, Strangford Lough. [In] Marine Biodiversity Data Portal - NI.
https://habitas.org/mbdp/sitephoto.php?item=_b205806.jpg. Accessed on 2026-11-04