# Help ID this mid-Atlantic invertebrate (no photo) **URL:** \ **Category:** Factual Questions\ **Created:** [September 22, 2008, 11:02am UTC](https://boards.straightdope.com/t/help-id-this-mid-atlantic-invertebrate-no-photo/464663 "2008-09-22T11:02:29Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [September 22, 2008, 11:02am UTC](https://boards.straightdope.com/t/help-id-this-mid-atlantic-invertebrate-no-photo/464663/1 "2008-09-22T11:02:29Z")
I found about six of these things in a half-hour on a Delaware beach. The beach is an Atlantic Ocean beach (not the DE Bay) and was experiencing a fairly serious northeast wind that was causing all sorts of stuff to wash up – including the black plastic bottom from an old two-liter bottle (remember those?). In addition to antique garbage, I found some invertebrates, and despite living at the beach for almost 20 years, I had never seen anything like them. They were small and round, about the size of a stack of two or three U.S. quarters, or an English one-pound coin, with dozens of short 2mm pink-and-white tentacles covering one side, a bright blue rim, and a semi-hard back side with brown and grey radial ridges, not much deeper than the designs engraved on a coin. One of the creatures I found had a notch torn radially into its body, and I got a good look at the cross-section of the hard back. It was not a shell – it was just the leathery exterior surface of a complex structure like the inside of a bird’s bones. The leathery texture of the hard plate reminded me of the “foot” plate on a univalve like a conch, but it was not actually a shell, or else it would not have torn. Less than a millimeter in from the hard/leathery side, the structure was clear stiff gel in an open-cell foam. There was no visible mouth, no visible sensory organs of any kind. It was as if a jellyfish, an anemone, and a sand dollar got together and made sweet sweet interspecies love. It was like no jellyfish, univalve, or bivalve I had ever seen. But maybe one of you Dopers knows what I’m talking about? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [September 22, 2008, 12:13pm UTC](https://boards.straightdope.com/t/help-id-this-mid-atlantic-invertebrate-no-photo/464663/2 "2008-09-22T12:13:01Z")
can’t really visualise what you’re describing, but could it have been some kind of chiton? > **[Chiton](https://en.wikipedia.org/wiki/Chiton)** > > See text. > Chitons (/ˈkaɪtənz/) are marine molluscs of varying size in the class Polyplacophora (/ˌpɒlipləˈkɒfərə/), formerly known as Amphineura. About 940 extant and 430 fossil species are recognized. > They are also sometimes known as sea cradles or coat-of-mail shells or suck-rocks, or more formally as loricates, polyplacophorans, and occasionally as polyplacophores. ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [September 23, 2008, 12:35am UTC](https://boards.straightdope.com/t/help-id-this-mid-atlantic-invertebrate-no-photo/464663/3 "2008-09-23T00:35:49Z")
Unlikely… the “shell” wasn’t really a shell of any sort. It was leathery on one side, but the leathery surface was more of a callous than a shell. The other side was covered edge-to-edge with soft, squishy white tentacles with pink tips, but they were very short compared to their diameter – maybe 2mm long and 1/2mm in diameter each. When it was not immersed in water the tentacles clumped together and deflated into a soft gelatinous mass. I sniffed it to see if it smelled any different from any of the various things that wash up on the shores of the world. It did not. The more research I do the more I’m convinced it’s either an echinoderm or a cnidarian, but I have no idea which direction to go. ---
**Author:** ![ReuvenB](https://avatars.discourse-cdn.com/v4/letter/r/9fc348/32.png) [@ReuvenB](https://boards.straightdope.com/u/ReuvenB)\ **Post date:** [September 23, 2008, 3:42pm UTC](https://boards.straightdope.com/t/help-id-this-mid-atlantic-invertebrate-no-photo/464663/4 "2008-09-23T15:42:17Z")
Could it have been a Portuguese Man o’ War? > **[Portuguese man o' war](https://en.wikipedia.org/wiki/Portuguese_Man_o%27_War)** > > The Portuguese man o' war (Physalia physalis), also known as the man-of-war, is a marine hydrozoan found in the Atlantic Ocean and the Indian Ocean. It is considered to be the same species as the Pacific man o' war or bluebottle, which is found mainly in the Pacific Ocean. The Portuguese man o' war is the only species in the genus Physalia, which in turn is the only genus in the family Physaliidae. > The Portuguese man o' war is a conspicuous member of the neuston, the community of organisms th... The ones I have seen have been purplish in color. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [September 23, 2008, 3:50pm UTC](https://boards.straightdope.com/t/help-id-this-mid-atlantic-invertebrate-no-photo/464663/5 "2008-09-23T15:50:16Z")
I herewith address the only portion of the OP I feel qualified to answer: > [@Jurph](#): > > the black plastic bottom from an old two-liter bottle (remember those?) Yep. ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [September 23, 2008, 6:13pm UTC](https://boards.straightdope.com/t/help-id-this-mid-atlantic-invertebrate-no-photo/464663/6 "2008-09-23T18:13:37Z")
> [@XWalrus2](#): > > Could it have been a Portuguese Man o’ War? > [Portuguese man o' war - Wikipedia](http://en.wikipedia.org/wiki/Portuguese_Man_o%27_War) > The ones I have seen have been purplish in color. Not likely… it didn’t have any air bladder, and I handled several of them extensively without even an itch. A Man O’ War – even a small one – should have left at least a red mark. Also, Man O’ War jellyfish are soft all over, and somewhat balloon-shaped. The creature I handled was like a small flattened lens: tough, rubbery, and brown-gray on the barely concave side; soft and gelatinous with pink and white tentacles on the convex side. I’m becoming more convinced that it was some kind of anemone, and the “hard” side was intended to grip rocks or the sea floor. But still, no proof! ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [September 23, 2008, 6:26pm UTC](https://boards.straightdope.com/t/help-id-this-mid-atlantic-invertebrate-no-photo/464663/7 "2008-09-23T18:26:32Z")
It bore a great resemblence to _Velella velella_ of the [Porpitidae](http://en.wikipedia.org/wiki/Porpitidae), but without the sail and much smaller. Could be that the strong northeaster pushed some of the young ones ashore out of season. ---
**Author:** ![mlees](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@mlees](https://boards.straightdope.com/u/mlees)\ **Post date:** [September 23, 2008, 6:35pm UTC](https://boards.straightdope.com/t/help-id-this-mid-atlantic-invertebrate-no-photo/464663/8 "2008-09-23T18:35:44Z")
baby sand dollars? [Sand Dollar](http://www.carolinanature.com/pix/sanddollar.html) ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [September 24, 2008, 1:37am UTC](https://boards.straightdope.com/t/help-id-this-mid-atlantic-invertebrate-no-photo/464663/9 "2008-09-24T01:37:42Z")
Okay, now I’m kicking myself. I looked right at the Wiki graphic for the Blue Button Porpitid, and didn’t think that it could be one of those with the long frilly tendrils torn off. Of course the beach was “experiencing a fairly serious northeast wind that was causing all sorts of stuff to wash up” but I didn’t even think that it could be part of a creature. [Here](http://www.flickr.com/photos/doubtful_guest/397387580/sizes/l/in/set-72157594553172409/) is a Flickr link to some blue button jellies washed ashore, tentacled side up. They look just like the ones I found! [Here](http://www.flickr.com/photos/doubtful_guest/397388404/sizes/o/) is one with the leathery dark brown side showing, and tentacles intact. Thanks for the suggestions, all.