February 21, 2006
From: Mike Neubig
Here are some shots of Bulla gouldiana.
Two individuals, several cm apart, were completely on top of the sand when I came across them on an evening beach dive at La Jolla Shores. The one I settled on to photo (dual HIDs, no strobes, custom lense) seemed to quickly exude and cover itself with a mucous blanket - and proceeded to dive into the sand. The head shot [upper right] with the eye spot was taken before this reaction to the bright light (?) began. The second shot is of the same individual heading under, head to the left. For the next few minutes, a free swimming sarcastic fringehead had my attention. When I looked back, the photo'd Bulla had vanished. The second individual was full below the level surface except for the anterior rhinophores, as in the lower photo.
The speckled patches seem similar to ones in Marli Wakeling's message about Melibe [#10999], in which the possibility of their being microscopic flatworm infestations is put forth. The erratic races on the Bulla 's shell are interesting too, especially how many seem to be half covered.
As the forum search turned up a few posts mentioning this species, but none with photos, I thought I would send these along for addition.
Locality: Valley-Sea-Toes, La Jolla Shores, 14 m, California, USA, Eastern Pacific Ocean, 16 February 2006, Gradually sloping sand bottom, 3 m from the "edge" of La Jolla Canyon. Length: 20 mm (shell). Photographer: Mike Neubig.
firstname.lastname@example.orgNeubig, M., 2006 (Feb 21) Bulla gouldiana from San Diego. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/15885
Thnaks for these interesting observations. Many of these bubble-shells have lare mucus glands at the front of the head which they use to make a mucus tube to crawl through in fine sand and mud, as you describe. The white speckled patches you mention are small galnds which can exude a white acidic secretion when the animal is disturbed. If look at the other photos of Melibe leonina on the Forum you will see that those in Marli's animal don't appear to be 'normal' for that species, so I suspected an external cause.
Concerning the lines across the shell which break up the pattern, they are growth lines, much like tree rings, which mark periods of growth and no growth on the shell. The uppermost one in your photo actually looks as though the edge of the shell was broken for awhile before regrowth occurred.
If anyone has a photo of Bulla gouldiana I could use for a Fact Sheet, it would be welcome.
Bulla gouldiana - egg laying
From: Kevin Lee, August 9, 2006
Bulla gouldiana aggregation, San Diego
From: Mike Neubig, May 25, 2006
Re: Gould's Bubble Snail - aggregation
From: Kevin Lee, May 25, 2006
Bulla gouldiana behaviour from San Diego
From: MIke Neubig, May 25, 2006
Gould's Bubble Snail - shell damage
From: Kevin Lee, May 3, 2006
Bulla gouldiana from La Jolla, California
From: Barbara Jeanne Lloyd, April 17, 2006
Bulla gouldiana - Gould's Bubble Snail
From: Barbara Jeanne Lloyd, February 27, 2006
Bulla gouldiana, detail of shell markings
From: Mike Neubig, February 27, 2006