what I have learned today: to know the by-the-wind sailor

[eub]

What are these things? They wash up on the beach in droves, are from one to half-a-dozen centimeters long, and come up if you google for beach blue diagonal sail.



They are Velella velella, the by-the-wind sailor, a colonial coelenterate like Physalia physalia.

http://www.cornwallwildlifetrust.org.uk/nature/marine/velella.htm

They exist in two forms, either left- or right-handed. The wind tends to distribute them into groups, depending whether they are either left- or right-handed, so strandings tend to be made up of one group.

http://jellieszone.com/velella.htm

Beneath the float is a grouping of several types of zooids, colored brown by the presence of zooxanthellae. A large central mouth is surrounded by shorter reproductive stalks with mouth openings that bud tiny adult medusae that produce eggs and sperm. [...] Dangling beneath the rim of the float are hollow tentacles that ensnare fish and invertebrate eggs, copepods and appendicularians.

Also,
http://www.pbs.org/odyssey/voice/20020407_vfts_transcript.html

Right whales sail by holding up their tails and letting the wind blow them along, but they seem to do this only as a form of play.

Comments

[eub.livejournal.com]

Bits and pieces on the web seem to be saying that the Pacific species Physalis utriculus has a single tentacle, and is the "bluebottle".

This page mentioned in passing that Velellae come ashore in Australia.

[aquaeri.livejournal.com]

Thanks for the research; I'll keep all this in mind. The handy household hint I can return is that if you get stung by a bluebottle, you pour vinegar on.

I'm not sure "getting stung" is the right thing to call it, anyway. In my case, the tail draped against my arm, and broke off the bluebottle, so I had this elegant shallow S-curved thin blue line along my arm that started to hurt like crazy. By the time I got out of the water, the tail itself had dissolved or washed away, and the line was just a row of little blue spots, still stinging away.