February 15, 2001
From: Bernard Picton
Here are a couple of pictures of Haminoea navicula. I'm fairly certain that the picture from France is of Haminoea hydatis. The pigmentation is different and the relative size of the parapodial lobes and cephalic shield look more like H. hydatis as described in Thompson. The posterior edge of the cephalic shield in H. navicula seems to be held clear of the shell whilst the photos of the French specimen shows a cleft shield pressed onto the shell, with the parapodial lobes clearly outside this. I note Thompson says the cleft shield and smaller parapodial lobes cannot be relied on to separate the species (? implying that older descriptions use these characters?) I've never seen H. hydatis myself.
UPPER PHOTO: Portmagee Channel, Valentia Is, Co Kerry, SW Ireland - May 1995
LOWER PHOTO: Kilmakilloge Harbour, Co. Kerry, Ireland - June 1984
email@example.comPicton, B. , 2001 (Feb 15) Haminoea navicula in the British Isles. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3804
The difference in relative size of parapodia is quite marked in these two species. I have made a Haminoea hydatis page for the Jean-Pierre's animals.