Pachymatisma johnstonia, Alcyonium digitatum. Site: E of Castle Head, Rathlin Island
 Pachymatisma johnstonia, Alcyonium digitatum. Event number: 19850625/01. Site: E of Castle Head, Rathlin Island. 1985-06-25. Photograph © Ulster Museum. (4/11) 
 Ulster Museum (2026). Photograph of Pachymatisma johnstonia, Alcyonium digitatum. Site: E of Castle Head, Rathlin Island. [In] Marine Biodiversity Data Portal - NI.
https://habitas.org/mbdp/sitephoto.php?item=niss_9958.jpg. Accessed on 2026-11-04