Elysia australis (Quoy & Gaimard, 1832) [Actaeon]

http://www.seaslugforum.net/showall/elysaust
http://www.nudibranch.com.au/pages/0840c.htm
http://www.scuba-equipment-usa.com/marine/NOV06/Australian_Elysia(Elysia_australis).html